T-cell redirecting bispecific antibodies for treatment of disease

ABSTRACT

The present invention concerns compositions and methods of use of T-cell redirecting complexes, with at least one binding site for a T-cell antigen and at least one binding site for an antigen on a diseased cell or pathogen. Preferably, the complex is a DNL™ complex. More preferably, the complex comprises a bispecific antibody (bsAb). Most preferably, the bsAb is an anti-CD3×anti-CD19 bispecific antibody, although antibodies against other T-cell antigens and/or disease-associated antigens may be used. The complex is capable of targeting effector T cells to induce T-cell-mediated cytotoxicity of cells associated with a disease, such as cancer, autoimmune disease or infectious disease. The cytotoxic immune response is enhanced by co-administration of interfon-based agents that comprise interferon-α, interferon-β, interferon-λ1, interferon-λ2 or interferon-λ3.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No. 15/062,919, filed Mar. 7, 2016, which was a divisional of U.S. patent application Ser. No. 13/966,450 (now issued U.S. Pat. No. 9,315,567), filed Aug. 14, 2013, which claimed the benefit under 35 U.S.C. 119(e) of provisional U.S. Patent Applications 61/682,965, filed Aug. 14, 2012, 61/733,268, filed Dec. 4, 2012, and 61/807,998, filed Apr. 3, 2013, each priority application incorporated herein by reference in its entirety.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted in ASCII format via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Aug. 9, 2013, is named IBC138US1_SL.txt and is 49,172 bytes in size.

FIELD

The present invention concerns compositions and methods of use of T-cell redirecting complexes. Preferably, the complexes comprise bispecific antibodies with one binding site for a T-cell antigen and another binding site for an antigen expressed on a diseased cell or pathogen. However, in alternative embodiments a different type of binding molecule may be utilized. In more preferred embodiments, the complexes are made as DOCK-AND-LOCK™ complexes, in which the components are attached together using the binding interaction between dimerization and docking domain (DDD) moieties from human protein kinase A (PKA) regulatory subunits and anchor domain (AD) moieties from AKAPs (A-kinase anchor proteins). However, other methods of making bispecific antibody complexes are known and may be used. The subject complexes may comprise one or more antibodies or antigen-binding antibody fragments that bind to an antigen expressed on T cells, such as CD3, and one or more antibodies or antibody fragments that bind to an antigen on a target cell, such as CD19, CD20, CD22, CD33, CD66e, EpCAM, HER2/neu, EGF receptor or another tumor-associated antigen (TAA), or an antigen expressed on a different diseased cell or pathogenic organism. The bispecific antibody redirects effector T cells to target diseased cells, tissues or pathogens and induces an immune response against the target. In more preferred embodiments, the bispecific antibody may be combined with one or more therapeutic agents that enhance the immune response. Most preferably, the therapeutic agent is an interferon, such as interferon-α, interferon-β or interferon-λ. The subject compositions and methods are of use for treating a wide variety of diseases and medical conditions, such as cancer, autoimmune disease, immune system dysfunction, graft-versus-host disease, organ transplant rejection or infectious disease.

BACKGROUND

Use of bispecific antibodies (bsAbs) to redirect effector T cells for the targeted killing of tumor cells has shown considerable promise both pre-clinically and clinically (see, e.g., Topp et al., 2012, Blood 120:5185-87; Bargou et al., 2008, Science 321:974-77). The bispecific antibodies contain a first binding site specific to CD3 for T-cell recruitment and activation and a second binding site for a targeted disease-associated antigen, such as CD19 (Bassan, 2012, Blood 120:5094-95). The bispecific antibody brings CD3⁺ T cells into direct contact with targeted disease cells and induces cell-mediated cytotoxicity (Bassan, 2012). Anti-CD3×anti-CD19 bispecific antibodies have been reported to produce a complete and durable molecular remission at very low concentrations in approximately 70% of adult patients with MRD⁺ ALL (Topp et al., 2012, Blood 120:5185-87). Bispecific antibodies recognizing gliomas and the CD3 epitope on T cells have been successfully used in treating brain tumors in human patients (Nitta, et al. Lancet 1990; 355:368-371).

Numerous methods to produce bispecific antibodies are known (see, e.g. U.S. Pat. No. 7,405,320). Bispecific antibodies can be produced by the quadroma method, which involves the fusion of two different hybridomas, each producing a monoclonal antibody recognizing a different antigenic site (Milstein and Cuello, Nature 1983; 305:537-540). The fused hybridomas are capable of synthesizing two different heavy chains and two different light chains, which can associate randomly to give a heterogeneous population of 10 different antibody structures of which only one of them, amounting to ⅛ of the total antibody molecules, will be bispecific, and therefore must be further purified from the other forms. Fused hybridomas are often less stable cytogenetically than the parent hybridomas, making the generation of a production cell line more problematic.

Another method for producing bispecific antibodies uses heterobifunctional cross-linkers to chemically tether two different monoclonal antibodies, so that the resulting hybrid conjugate will bind to two different targets (Staerz, et al. Nature 1985; 314:628-631; Perez, et al. Nature 1985; 316:354-356). Bispecific antibodies generated by this approach are essentially heteroconjugates of two IgG molecules, which diffuse slowly into tissues and are rapidly removed from the circulation. Bispecific antibodies can also be produced by reduction of each of two parental monoclonal antibodies to the respective half molecules, which are then mixed and allowed to reoxidize to obtain the hybrid structure (Staerz and Bevan. Proc Natl Acad Sci USA 1986; 83:1453-1457). An alternative approach involves chemically cross-linking two or three separately purified Fab′ fragments using appropriate linkers. All these chemical methods are undesirable for commercial development due to high manufacturing cost, laborious production process, extensive purification steps, low yields (<20%), and heterogeneous products.

Discrete V_(H) and V_(L) domains of antibodies produced by recombinant DNA technology may pair with each other to form a dimer (recombinant Fv fragment) with binding capability (U.S. Pat. No. 4,642,334). However, such non-covalently associated molecules are not sufficiently stable under physiological conditions to have any practical use. Cognate V_(H) and V_(L) domains can be joined with a peptide linker of appropriate composition and length (usually consisting of more than 12 amino acid residues) to form a single-chain Fv (scFv) with binding activity. Methods of manufacturing scFv-based agents of multivalency and multispecificity by varying the linker length were disclosed in U.S. Pat. No. 5,844,094, U.S. Pat. No. 5,837,242 and WO 98/44001. Common problems that have been frequently associated with generating scFv-based agents of multivalency and multispecificity are low expression levels, heterogeneous products, instability in solution leading to aggregates, instability in serum, and impaired affinity.

Several bispecific antibodies targeting CD3 and CD19 are in clinical development. An scFv-based bispecific antibody construct, known as BITE® (Bispecific T-cell Engager) employs a single polypeptide containing 2 antigen-binding specificities, each contributed by a cognate VH and VL, linked in tandem via a flexible linker (see, e.g., Nagorsen et al., 2009, Leukemia & Lymphoma 50:886-91; Amann et al., 2009, J Immunother 32:453-64; Baeuerle and Reinhardt, 2009, Cancer Res 69:4941-44). Another bispecific antibody called DART® (Dual-Affinity Re-Targeting) utilizes a disulfide-stabilized diabody design (see, e.g., Moore et al., 2011, Blood 117:4542-51; Veri et al., 2010, Arthritis Rheum 62:1933-43). Both BITE® and DART® exhibit fast blood clearance due to their small size (˜55 kDa), which requires frequent administration to maintain therapeutic levels of the bispecific antibodies.

A need exists for methods and compositions to generate improved bispecific antibody complexes with longer T_(1/2), better pharmacokinetic properties, increased in vivo stability and/or improved in vivo efficacy. A further need exists for compositions and methods to improve the efficacy of anti-CD3 based bispecific antibodies for therapeutic use in cancer and other diseases, for example by co-administering adjunct therapeutic agents, such as interferons, that enhance the efficacy of the bispecific antibody constructs.

SUMMARY

The present invention relates to compositions and methods of use of novel, T-cell redirecting complexes. Preferably, the complexes comprise bispecific antibodies (bsAbs), preferably comprising an anti-CD3 scFv or other antibody fragment attached to a stabilized F(ab)₂ or other antibody fragment. An exemplary design disclosed in the Examples below combined an anti-CD3 scFv with an anti-CD19 F(ab)₂ to form a construct designated (19)-3s, which specifically targeted B cells. Other bsAbs combining anti-CD3 with antibody fragments against other tumor-associated antigens, discussed in more detail below, are of use in targeted T cell immunotherapy of various solid tumors. The advantages of this design include bivalent binding to tumor cells, a larger size (˜130 kDa) to preclude rapid renal clearance, and potent T-cell mediated cytotoxicity. The bsAbs mediate the formation of immunological synapses between T cells and cognate target cells, induce T-cell activation and proliferation in the presence of target cells, redirect potent T-cell mediated killing of target cells in vitro and inhibit growth of human tumors in vivo.

A preferred embodiment concerns the subject bispecific antibodies produced as trivalent DNL™ complexes, with longer T_(1/2), better pharmacokinetic properties and increased in vivo stability. Methods for production and use of DNL™ complexes, comprising dimers of DDD moieties from human PKA regulatory subunits RIα, RIβ, RIIα or RIIβ, bound to AD moieties from AKAPs, are well known (see, e.g., U.S. Pat. Nos. 7,550,143; 7,521,056; 7,534,866; 7,527,787; 7,666,400; 7,906,118; 7,901,680; 8,003,111 and 8,034,352, the Examples section of each incorporated herein by reference.) By attaching different effector moieties, such as antibodies or antibody fragments, to the DDD and AD moieties, DNL™ complexes comprising virtually any combination of effectors may be constructed and used.

The antibodies of use can be of various isotypes, preferably human IgG1, IgG2, IgG3 or IgG4, more preferably comprising human IgG1 hinge and constant region sequences. The antibodies or fragments thereof can be chimeric human-mouse, humanized (human framework and murine hypervariable (CDR) regions), or fully human, as well as variations thereof, such as half-IgG4 antibodies (referred to as “unibodies”), as described by van der Neut Kolfschoten et al. (Science 2007; 317:1554-1557). More preferably, the antibodies or fragments thereof may be designed or selected to comprise human constant region sequences that belong to specific allotypes, which may result in reduced immunogenicity when administered to a human subject. Preferred allotypes for administration include a non-G1m1 allotype (nG1m1), such as G1m3, G1m3,1, G1m3,2 or G1m3,1,2. More preferably, the allotype is selected from the group consisting of the nG1m1, G1m3, nG1m1,2 and Km3 allotypes.

In various embodiments, the T-cell redirecting bispecific antibodies may be administered to a subject for treatment of a condition. The skilled artisan will realize that any condition that may be treated with a T-cell redirecting bispecific antibodies may be treated with the subject compositions and methods. Exemplary conditions include, but are not limited to, cancer, hyperplasia, neurodegenerative disease, Alzheimer's disease, cardiovascular disease, metabolic disease, vasculitis, viral infection, fungal infection, bacterial infection, diabetic retinopathy, macular degeneration, autoimmune disease, edema, pulmonary hypertension, sepsis, myocardial angiogenesis, plaque neovascularization, restenosis, neointima formation after vascular trauma, telangiectasia, hemophiliac joints, angiofibroma, fibrosis associated with chronic inflammation, lung fibrosis, deep venous thrombosis or wound granulation.

In particular embodiments, the bsAbs may be of use to treat autoimmune disease, such as acute idiopathic thrombocytopenic purpura, chronic idiopathic thrombocytopenic purpura, dermatomyositis, Sydenham's chorea, myasthenia gravis, systemic lupus erythematosus, lupus nephritis, rheumatic fever, polyglandular syndromes, bullous pemphigoid, type 1 diabetes, type 2 diabetes, Henoch-Schonlein purpura, post-streptococcalnephritis, erythema nodosurn, Takayasu's arteritis, Addison's disease, rheumatoid arthritis, multiple sclerosis, sarcoidosis, ulcerative colitis, erythema multiforme, IgA nephropathy, polyarteritis nodosa, ankylosing spondylitis, Goodpasture's syndrome, thromboangitis obliterans, Sjögren's syndrome, primary biliary cirrhosis, Hashimoto's thyroiditis, thyrotoxicosis, scleroderma, chronic active hepatitis, polymyositis/dermatomyositis, polychondritis, pemphigus vulgaris, Wegener's granulomatosis, membranous nephropathy, amyotrophic lateral sclerosis, tabes dorsalis, giant cell arteritis/polymyalgia, pernicious anemia, rapidly progressive glomerulonephritis, psoriasis or fibrosing alveolitis.

In certain embodiments, the bsAbs may be of use for therapy of cancer. It is anticipated that any type of tumor and any type of tumor antigen may be targeted. Exemplary types of cancers that may be targeted include acute lymphoblastic leukemia, acute myelogenous leukemia, biliary cancer, breast cancer, cervical cancer, chronic lymphocytic leukemia, chronic myelogenous leukemia, colorectal cancer, endometrial cancer, esophageal, gastric, head and neck cancer, Hodgkin's lymphoma, lung cancer, medullary thyroid cancer, non-Hodgkin's lymphoma, multiple myeloma, renal cancer, ovarian cancer, pancreatic cancer, glioma, melanoma, liver cancer, prostate cancer, and urinary bladder cancer. However, the skilled artisan will realize that tumor-associated antigens are known for virtually any type of cancer.

Tumor-associated antigens that may be targeted include, but are not limited to, alpha-fetoprotein (AFP), α-actinin-4, A3, antigen specific for A33 antibody, ART-4, B7, Ba 733, BAGE, BrE3-antigen, CA125, CAMEL, CAP-1, carbonic anhydrase IX, CASP-8/m, CCL19, CCL21, CD1, CD1a, CD2, CD3, CD4, CD5, CD8, CD11A, CD14, CD15, CD16, CD18, CD19, CD20, CD21, CD22, CD23, CD25, CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD44, CD45, CD46, CD52, CD54, CD55, CD59, CD64, CD66a-e, CD67, CD70, CD70L, CD74, CD79a, CD80, CD83, CD95, CD126, CD132, CD133, CD138, CD147, CD154, CDC27, CDK-4/m, CDKN2A, CTLA-4, CXCR4, CXCR7, CXCL12, HIF-1α, colon-specific antigen-p (CSAp), CEA (CEACAM5), CEACAM6, c-Met, DAM, EGFR, EGFRvIII, EGP-1 (TROP-2), EGP-2, ELF2-M, Ep-CAM, fibroblast growth factor (FGF), Flt-1, Flt-3, folate receptor, G250 antigen, GAGE, gp100, GRO-β, HLA-DR, HM1.24, human chorionic gonadotropin (HCG) and its subunits, HER2/neu, HMGB-1, hypoxia inducible factor (HIF-1), HSP70-2M, HST-2, Ia, IGF-1R, IFN-γ, IFN-α, IFN-β, IFN-λ, IL-4R, IL-6R, IL-13R, IL-15R, IL-17R, IL-18R, IL-2, IL-6, IL-8, IL-12, IL-15, IL-17, IL-18, IL-23, IL-25, insulin-like growth factor-1 (IGF-1), KC4-antigen, KS-1-antigen, KS1-4, Le-Y, LDR/FUT, macrophage migration inhibitory factor (MIF), MAGE, MAGE-3, MART-1, MART-2, NY-ESO-1, TRAG-3, mCRP, MCP-1, MIP-1A, MIP-1B, MIF, MUC1, MUC2, MUC3, MUC4, MUC5ac, MUC13, MUC16, MUM-1/2, MUM-3, NCA66, NCA95, NCA90, pancreatic cancer mucin, PD-1 receptor, placental growth factor, p53, PLAGL2, prostatic acid phosphatase, PSA, PRAME, PSMA, P1GF, ILGF, ILGF-1R, IL-6, IL-25, RS5, RANTES, T101, SAGE, S100, survivin, survivin-2B, TAC, TAG-72, tenascin, TRAIL receptors, TNF-α, Tn antigen, Thomson-Friedenreich antigens, tumor necrosis antigens, VEGFR, ED-B fibronectin, WT-1, 17-1A-antigen, complement factors C3, C3a, C3b, C5a, C5, an angiogenesis marker, bcl-2, bcl-6, Kras, an oncogene marker and an oncogene product (see, e.g., Sensi et al., Clin Cancer Res 2006, 12:5023-32; Parmiani et al., J Immunol 2007, 178:1975-79; Novellino et al. Cancer Immunol Immunother 2005, 54:187-207).

Exemplary antibodies that may be used in combination with an anti-CD3 antibody or fragment thereof include, but are not limited to, hA19 (anti-CD19, U.S. Pat. No. 7,109,304), hR1 (anti-IGF-1R, U.S. patent application Ser. No. 12/722,645, filed Mar. 12, 2010), hPAM4 (anti-mucin, U.S. Pat. No. 7,282,567), hA20 (anti-CD20, U.S. Pat. No. 7,251,164), hIMMU31 (anti-AFP, U.S. Pat. No. 7,300,655), hLL1 (anti-CD74, U.S. Pat. No. 7,312,318), hLL2 (anti-CD22, U.S. Pat. No. 7,074,403), hMu-9 (anti-CSAp, U.S. Pat. No. 7,387,773), hL243 (anti-HLA-DR, U.S. Pat. No. 7,612,180), hMN-14 (anti-CEACAM5, U.S. Pat. No. 6,676,924), hMN-15 (anti-CEACAM6, U.S. Pat. No. 7,541,440), hRS7 (anti-EGP-1, U.S. Pat. No. 7,238,785), hMN-3 (anti-CEACAM6, U.S. Pat. No. 7,541,440), Ab124 and Ab125 (anti-CXCR4, U.S. Pat. No. 7,138,496), the Examples section of each cited patent or application incorporated herein by reference. Alternative antibodies that may be attached to the anti-CD3 for treatment of various disease states include, but are not limited to, abciximab (anti-glycoprotein IIb/IIIa), alemtuzumab (anti-CD52), bevacizumab (anti-VEGF), cetuximab (anti-EGFR), gemtuzumab (anti-CD33), ibritumomab (anti-CD20), panitumumab (anti-EGFR), rituximab (anti-CD20), tositumomab (anti-CD20), trastuzumab (anti-ErbB2), lambrolizumab (anti-PD-1 receptor), nivolumab (anti-PD-1 receptor), ipilimumab (anti-CTLA-4), abagovomab (anti-CA-125), adecatumumab (anti-EpCAM), atlizumab (anti-IL-6 receptor), benralizumab (anti-CD125), obinutuzumab (GA101, anti-CD20), CC49 (anti-TAG-72), AB-PG1-XG1-026 (anti-PSMA, U.S. patent application Ser. No. 11/983,372, deposited as ATCC PTA-4405 and PTA-4406), D2/B (anti-PSMA, WO 2009/130575), tocilizumab (anti-IL-6 receptor), basiliximab (anti-CD25), daclizumab (anti-CD25), efalizumab (anti-CD11a), GA101 (anti-CD20; Glycart Roche), atalizumab (anti-α4 integrin), omalizumab (anti-IgE); anti-TNF-α antibodies such as CDP571 (Ofei et al., 2011, Diabetes 45:881-85), MTNFAI, M2TNFAI, M3TNFAI, M3TNFABI, M302B, M303 (Thermo Scientific, Rockford, Ill.), infliximab (Centocor, Malvern, Pa.), certolizumab pegol (UCB, Brussels, Belgium), anti-CD40L (UCB, Brussels, Belgium), adalimumab (Abbott, Abbott Park, Ill.), BENLYSTA® (Human Genome Sciences); antibodies for therapy of Alzheimer's disease such as Alz 50 (Ksiezak-Reding et al., 1987, J Biol Chem 263:7943-47), gantenerumab, solanezumab and infliximab; anti-fibrin antibodies like 59D8, T2G1s, MH1; anti-CD38 antibodies such as MOR03087 (MorphoSys AG), MOR202 (Celgene), HuMax-CD38 (Genmab) or daratumumab (Johnson & Johnson); anti-HIV antibodies such as P4/D10 (U.S. Pat. No. 8,333,971), Ab 75, Ab 76, Ab 77 (Paulik et al., 1999, Biochem Pharmacol 58:1781-90), as well as the anti-HIV antibodies described and sold by Polymun (Vienna, Austria), also described in U.S. Pat. No. 5,831,034, U.S. Pat. No. 5,911,989, and Vcelar et al., AIDS 2007; 21(16):2161-2170 and Joos et al., Antimicrob. Agents Chemother. 2006; 50(5):1773-9.

In other embodiments, the subject bsAbs may be of use to treat subjects infected with pathogenic organisms, such as bacteria, viruses or fungi. Exemplary fungi that may be treated include Microsporum, Trichophyton, Epidermophyton, Sporothrix schenckii, Cryptococcus neoformans, Coccidioides immitis, Histoplasma capsulatum, Blastomyces dermatitidis or Candida albican. Exemplary viruses include human immunodeficiency virus (HIV), herpes virus, cytomegalovirus, rabies virus, influenza virus, human papilloma virus, hepatitis B virus, hepatitis C virus, Sendai virus, feline leukemia virus, Reo virus, polio virus, human serum parvo-like virus, simian virus 40, respiratory syncytial virus, mouse mammary tumor virus, Varicella-Zoster virus, dengue virus, rubella virus, measles virus, adenovirus, human T-cell leukemia viruses, Epstein-Barr virus, murine leukemia virus, mumps virus, vesicular stomatitis virus, Sindbis virus, lymphocytic choriomeningitis virus or blue tongue virus. Exemplary bacteria include Bacillus anthracis, Streptococcus agalactiae, Legionella pneumophilia, Streptococcus pyogenes, Escherichia coli, Neisseria gonorrhoeae, Neisseria meningitidis, Pneumococcus spp., Hemophilis influenzae B, Treponema pallidum, Lyme disease spirochetes, Pseudomonas aeruginosa, Mycobacterium leprae, Brucella abortus, Mycobacterium tuberculosis or a Mycoplasma. Known antibodies against pathogens include, but are not limited to, P4D10 (anti-HIV), CR6261 (anti-influenza), exbivirumab (anti-hepatitis B), felvizumab (anti-respiratory syncytial virus), foravirumab (anti-rabies virus), motavizumab (anti-respiratory syncytial virus), palivizumab (anti-respiratory syncytial virus), panobacumab (anti-Pseudomonas), rafivirumab (anti-rabies virus), regavirumab (anti-cytomegalovirus), sevirumab (anti-cytomegalovirus), tivirumab (anti-hepatitis B), and urtoxazumab (anti-E. coli).

The subject bsAbs may be administered in combination with one or more immunomodulators to enhance the immune response. Immunomodulators may include, but are not limited to, a cytokine, a chemokine, a stem cell growth factor, a lymphotoxin, an hematopoietic factor, a colony stimulating factor (CSF), erythropoietin, thrombopoietin, tumor necrosis factor-α (TNF), TNF-β, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage-colony stimulating factor (GM-CSF), interferon-α, interferon-β, interferon-γ, interferon-λ, stem cell growth factor designated “S1 factor”, human growth hormone, N-methionyl human growth hormone, bovine growth hormone, parathyroid hormone, thyroxine, insulin, proinsulin, relaxin, prorelaxin, follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), luteinizing hormone (LH), hepatic growth factor, prostaglandin, fibroblast growth factor, prolactin, placental lactogen, OB protein, mullerian-inhibiting substance, mouse gonadotropin-associated peptide, inhibin, activin, vascular endothelial growth factor, integrin, NGF-β, platelet-growth factor, TGF-α, TGF-β, insulin-like growth factor-I, insulin-like growth factor-II, macrophage-CSF (M-CSF), IL-1, IL-1α, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12, IL-13, IL-14, IL-15, IL-16, IL-17, IL-18, IL-21, IL-25, LIF, FLT-3, angiostatin, thrombospondin, endostatin, or lymphotoxin. In certain embodiments, the bispecific antibody or antibody fragment may be attached to an immunomodulator, such as a cytokine. Cytokine complexes are disclosed, for example, in U.S. Pat. Nos. 7,906,118 and 8,034,352, the Examples section of each incorporated herein by reference. Preferred immunomodulators that may be used in combination with T-cell redirecting bsAbs include interferon-α, interferon-β and interferon-λ.

Although the antibody or other binding molecule specific for effector T cells preferably binds to the CD3 antigen, other antigens expressed on effector T cells are known and may be targeted by the T-cell redirecting complex. Exemplary T-cell antigens include, but are not limited to, CD2, CD3, CD4, CD5, CD6, CD8, CD25, CD28, CD30, CD40, CD40L, CD44, CD45, CD69 and CD90.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings form part of the present specification and are included to further demonstrate certain embodiments of the present invention. The embodiments may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.

FIG. 1. Schematic diagram of formation of DOCK-AND-LOCK™ complex comprising anti-CD19 F(ab)₂×anti-CD3 scFv.

FIG. 2. Immune synapse formation between Daudi Burkitt lymphoma and T cells, mediated by (19)-3s. Freshly isolated T cells were combined with Daudi cells at an E:T ratio of 2.5:1. Cells were treated with 0, 1 or 5 μg/mL of (19)-3s for 30 min at room temperature prior to analysis by flow cytometry. Anti-CD20-FITC and anti-CD7-APC were used to identify Daudi and T cells, respectively. Co-binding was indicated as the % of CD20⁺/CD7⁺ events. After treatment with (19)-3s, 45.5% of flow events were CD20/CD7 dual-positive, indicating synapsed Daudi and T cells (A), compared to 2% measured for the mixed cells without antibody (B). Addition of (19)-3s resulted in association of >90% of the Daudi with T cells (C).

FIG. 3. Jurkat (T cells) and Daudi (B cells) were combined at a 1:1 ratio, treated with 0.1 μg/mL (19)-3s for 30 minutes and stained with anti-CD20-FITC (A) and anti-CD3-PE (B), prior to analysis by fluorescence microscopy. The merged image (C) reveals synapse formation between green-stained Daudi and red-stained Jurkat cells. Synapse formation was not evident in the absence of (19)-3s (D).

FIG. 4. Dose response analysis of (19)-3s mediated cell-to-cell association of Daudi and Jurkat cells.

FIG. 5. Comparison of cell-to-cell association mediated by (A) BITE™, DART™ and (B) (19)-3s. The data for BITE™ and DART™ was taken from Moore et al. (2011, Blood 117:4542-4551.

FIG. 6. Synapse formation between T cells and Capan-1 pancreatic cancer cells mediated by (A) (19)-3s control bsAb compared to (B) (M1)-3s MUCSAC and (C) (E1)-3s TROP-2 targeting bsAbs. CFSE-labeled Capan-1 cells were coincubated with PKH26-labeled Jurkat in the presence of the bsAbs.

FIG. 7. T-cell activation by (19)-3s. Upregulation of CD69 expression is an early event in T-cell activation. Daudi cells combined with PBMCs (A), or purified T cells (B), as well as purified T cells alone (C) were treated overnight with the indicated antibodies, and stained with anti-CD3-PE and anti-CD69-APC, prior to analysis by flow cytometry. CD69 expression was evaluated following gating of T cells by forward vs. side scattering and anti-CD3 staining. (A) Combination of Daudi cells with an equal number of PBMCs resulted in 1.6% CD69+ T cells. Addition of 3 ng/mL (19)-3s induced 27% CD69+ T cells. Neither a control construct [(M1)-35], which comprises the Okt3-scFv-AD2 module fused with a non-targeting F(ab)₂, nor the hA19-Fab-DDD2 module, induced T-cell activation. (B) Treatment of Daudi and purified T cells with (M1)-3s or hA19-Fab-DDD2 did not increase the number of CD69+ T cells (<4%), compared to the untreated cell mixture. Alternatively, (19)-3s induced robust T-cell activation, producing 80% CD69+ cells. (C) Without the addition of Daudi (target) cells, (19)-3s did not induce CD69 expression and T-cell activation. These results demonstrate that (19)-3s-mediated synapse formation between T cells and target cells is both required and sufficient for T-cell activation.

FIG. 8. Induction of T-cell proliferation by (19)-3s. (A) PBMCs were incubated with 3 nM or 30 pM of (19)-3s, compared to IL-2/PHA positive control and (14)-3s (non-target-binding control). (B) T cell proliferation was not observed in PBMCs depleted of B cells, indicating that target cells (B cells) are required for T-cell activation and proliferation.

FIG. 9. In vitro cytotoxicity of (19)-3s T-cell redirecting bsAbs. Dose-response curves for cytotoxicity to Nalm-6, Raji, Ramos and Namalwa cancer cells were determined for the (A) (19)-3s and (B) (14)-3s (non-targeting) DNL™ bsAb complexes. (C) Consistent results were observed using PBMCs, or T cells, obtained from two different donors and Nalm-6 cancer cells.

FIG. 10. In vitro cytotoxicity of (20)-3s, (22)-3s and (C2)-3s T-cell redirecting bsAbs. Dose-response curves were determined for cytotoxicity to (A) Namalwa, (B) Jeko, and (C) Daudi cells induced by (20)-3s, (22)-3s and (C2)-3s T-cell redirecting bsAbs.

FIG. 11. In vitro cytotoxicity of T-cell redirecting bsAbs in solid tumor cell lines. (A) Dose-response curves were determined for cytotoxicity to the LS174T colon adenocarcinoma cell line for the (14)-3s bsAb, compared to non-targeting (19)-3s bsAb. (B) Dose-response curves were determined for cytotoxicity to the Capan-1 pancreatic adenocarcinoma cell line for the (E1)-35 bsAb, compared to non-targeting (19)-3s bsAb. (C) Dose-response curves were determined for cytotoxicity to the NCI-N87 gastric carcinoma cell line for the (E1)-3s and (15)-3s bsAbs, compared to non-targeting (19)-3s bsAb.

FIG. 12. Summary of in vitro cytotoxicity data for T-cell redirecting bsAbs in cancer cell lines.

FIG. 13. In vivo retargeting of Raji lymphoma xenografts using (19)-3s bsAb. NOD/SCID mice bearing Raji Burkitt lymphoma (1×10⁶ cells) xenografts, reconstituted with human PBMCs (5×10⁶ cells) were treated with (19)-3s for only 1 week, administered as indicated by the arrows: (A) untreated, (B) treated with a single dose of 130 μg, (C) treated 3× with 43 μg per dose, (D) treated 5× with 26 μg per dose.

FIG. 14. Effect of repeated dosing on in vivo retargeting of Raji lymphoma xenografts using (19)-3s bsAb. NOD/SCID mouse xenografts were prepared as indicated in the legend to FIG. 13. The (19)-3s was administered as indicated by the arrows: (A) untreated, (B) treated 2× with 130 μg per dose of (19)-3s administered i.v., (C) treated 2× with 130 μg per dose of (19)-3s administered s.c., (D) treated 4× with 65 μg per dose of (19)-3s administered i.v., (E) treated 6× with 43 μg per dose of (19)-3s administered i.v., (F) treated 6× with 43 μg per dose of control (M1)-3s administered i.v.

FIG. 15. In vivo efficacy of T-cell retargeting bsAbs in solid tumor xenografts. NOD/SCID mouse xenografts were prepared with LS174T colon adenocarcinoma (A, B) or Capan-1 pancreatic carcinoma (C, D). (A) Mice were administered T cells only without bsAb. (B) Mice were treated with (E1)-3s bsAb as indicated. (C) Mice were administered PBMCs only without bsAb. (D) Mice were treated with (14)-3s bsAb as indicated.

FIG. 16. In vivo inhibition of tumor growth by (E1)-3s DNL™ complex in the presence or absence of interferon-α. Capan-1 pancreatic carcinoma xenografts in NOD/SCID mice were treated with anti-TROP-2×anti-CD3 bsAb with or without added interferon-α. (A) The interferon-α was added in the form of a TROP-2 targeting DNL™ complex. (B) The interferon-α was added as the commercially available PEGASYS® (peginterferon alfa-2a).

FIG. 17. Survival curves for NOD/SCID mice treated with (E1)-3s with or without interferon-α. Controls were untreated or treated with interferon-α alone.

DETAILED DESCRIPTION

Definitions

Unless otherwise specified, “a” or “an” means “one or more”.

As used herein, the terms “and” and “or” may be used to mean either the conjunctive or disjunctive. That is, both terms should be understood as equivalent to “and/or” unless otherwise stated.

A “therapeutic agent” is an atom, molecule, or compound that is useful in the treatment of a disease. Examples of therapeutic agents include antibodies, antibody fragments, peptides, drugs, toxins, enzymes, nucleases, hormones, immunomodulators, antisense oligonucleotides, small interfering RNA (siRNA), chelators, boron compounds, photoactive agents, dyes, and radioisotopes.

An “antibody” as used herein refers to a full-length (i.e., naturally occurring or formed by normal immunoglobulin gene fragment recombinatorial processes) immunoglobulin molecule (e.g., an IgG antibody) or an immunologically active (i.e., specifically binding) portion of an immunoglobulin molecule, like an antibody fragment. An “antibody” includes monoclonal, polyclonal, bispecific, multispecific, murine, chimeric, humanized and human antibodies.

A “naked antibody” is an antibody or antigen binding fragment thereof that is not attached to a therapeutic or diagnostic agent. The Fc portion of an intact naked antibody can provide effector functions, such as complement fixation and ADCC (see, e.g., Markrides, Pharmacol Rev 50:59-87, 1998). Other mechanisms by which naked antibodies induce cell death may include apoptosis. (Vaswani and Hamilton, Ann Allergy Asthma Immunol 81: 105-119, 1998.)

An “antibody fragment” is a portion of an intact antibody such as F(ab′)₂, F(ab)₂, Fab′, Fab, Fv, scFv, dAb and the like. Regardless of structure, an antibody fragment binds with the same antigen that is recognized by the full-length antibody. For example, antibody fragments include isolated fragments consisting of the variable regions, such as the “Fv” fragments consisting of the variable regions of the heavy and light chains or recombinant single chain polypeptide molecules in which light and heavy variable regions are connected by a peptide linker (“scFv proteins”). “Single-chain antibodies”, often abbreviated as “scFv” consist of a polypeptide chain that comprises both a V_(H) and a V_(L) domain which interact to form an antigen-binding site. The V_(H) and V_(L) domains are usually linked by a peptide of 1 to 25 amino acid residues. Antibody fragments also include diabodies, triabodies and single domain antibodies (dAb).

A “chimeric antibody” is a recombinant protein that contains the variable domains including the complementarity determining regions (CDRs) of an antibody derived from one species, preferably a rodent antibody, while the constant domains of the antibody molecule are derived from those of a human antibody. For veterinary applications, the constant domains of the chimeric antibody may be derived from that of other species, such as a cat or dog.

A “humanized antibody” is a recombinant protein in which the CDRs from an antibody from one species; e.g., a rodent antibody, are transferred from the heavy and light variable chains of the rodent antibody into human heavy and light variable domains, including human framework region (FR) sequences. The constant domains of the antibody molecule are derived from those of a human antibody. To maintain binding activity, a limited number of FR amino acid residues from the parent (e.g., murine) antibody may be substituted for the corresponding human FR residues.

A “human antibody” is an antibody obtained from transgenic mice that have been genetically engineered to produce specific human antibodies in response to antigenic challenge. In this technique, elements of the human heavy and light chain locus are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions of the endogenous heavy chain and light chain loci. The transgenic mice can synthesize human antibodies specific for human antigens, and the mice can be used to produce human antibody-secreting hybridomas. Methods for obtaining human antibodies from transgenic mice are described by Green et al., Nature Genet. 7:13 (1994), Lonberg et al., Nature 368:856 (1994), and Taylor et al., Int. Immun. 6:579 (1994). A human antibody also can be constructed by genetic or chromosomal transfection methods, as well as phage display technology, all of which are known in the art. (See, e.g., McCafferty et al., 1990, Nature 348:552-553 for the production of human antibodies and fragments thereof in vitro, from immunoglobulin variable domain gene repertoires from unimmunized donors). In this technique, antibody variable domain genes are cloned in-frame into either a major or minor coat protein gene of a filamentous bacteriophage, and displayed as functional antibody fragments on the surface of the phage particle. Because the filamentous particle contains a single-stranded DNA copy of the phage genome, selections based on the functional properties of the antibody also result in selection of the gene encoding the antibody exhibiting those properties. In this way, the phage mimics some of the properties of the B cell. Phage display can be performed in a variety of formats, for their review, see, e.g. Johnson and Chiswell, Current Opinion in Structural Biology 3:5564-571 (1993). Human antibodies may also be generated by in vitro activated B cells. (See, U.S. Pat. Nos. 5,567,610 and 5,229,275).

As used herein, the term “antibody fusion protein” is a recombinantly produced antigen-binding molecule in which an antibody or antibody fragment is linked to another protein or peptide, such as the same or different antibody or antibody fragment or a DDD or AD peptide. The fusion protein may comprise a single antibody component, a multivalent or multispecific combination of different antibody components or multiple copies of the same antibody component. The fusion protein may additionally comprise an antibody or an antibody fragment and a therapeutic agent. Examples of therapeutic agents suitable for such fusion proteins include immunomodulators and toxins. One preferred toxin comprises a ribonuclease (RNase), preferably a recombinant RNase. A preferred immunomodulator might be an interferon, such as interferon-α, interferon-β or interferon-λ.

A “multispecific antibody” is an antibody that can bind simultaneously to at least two targets that are of different structure, e.g., two different antigens, two different epitopes on the same antigen, or a hapten and/or an antigen or epitope. A “multivalent antibody” is an antibody that can bind simultaneously to at least two targets that are of the same or different structure. Valency indicates how many binding arms or sites the antibody has to a single antigen or epitope; i.e., monovalent, bivalent, trivalent or multivalent. The multivalency of the antibody means that it can take advantage of multiple interactions in binding to an antigen, thus increasing the avidity of binding to the antigen. Specificity indicates how many antigens or epitopes an antibody is able to bind; i.e., monospecific, bispecific, trispecific, multispecific. Using these definitions, a natural antibody, e.g., an IgG, is bivalent because it has two binding arms but is monospecific because it binds to one epitope. Multispecific, multivalent antibodies are constructs that have more than one binding site of different specificity.

A “bispecific antibody” is an antibody that can bind simultaneously to two targets which are of different structure. Bispecific antibodies (bsAb) and bispecific antibody fragments (bsFab) may have at least one arm that specifically binds to, for example, a T cell, and at least one other arm that specifically binds to an antigen produced by or associated with a diseased cell, tissue, organ or pathogen, for example a tumor-associated antigen. A variety of bispecific antibodies can be produced using molecular engineering.

An antibody preparation, or a composition described herein, is said to be administered in a “therapeutically effective amount” if the amount administered is physiologically significant. An agent is physiologically significant if its presence results in a detectable change in the physiology of a recipient subject. In particular embodiments, an antibody preparation is physiologically significant if its presence invokes an antitumor response or mitigates the signs and symptoms of an autoimmune or infectious disease state. A physiologically significant effect could also be the evocation of a humoral and/or cellular immune response in the recipient subject leading to growth inhibition or death of target cells.

Interferon Therapy

In various embodiments, the subject T-cell redirecting bsAbs may be used in combination with one or more interferons, such as interferon-α, interferon-β or interferon-λ. Human interferons are well known in the art and the amino acid sequences of human interferons may be readily obtained from public databases (e.g., GenBank Accession Nos. AAA52716.1; AAA52724; AAC41702.1; EAW56871.1; EAW56870.1; EAW56869.1). Human interferons may also be commercially obtained from a variety of vendors (e.g., Cell Signaling Technology, Inc., Danvers, Mass.; Genentech, South San Francisco, Calif.; EMD Millipore, Billerica, Mass.).

Interferon-α (IFNα) has been reported to have anti-tumor activity in animal models of cancer (Ferrantini et al., 1994, J Immunol 153:4604-15) and human cancer patients (Gutterman et al., 1980, Ann Intern Med 93:399-406). IFNα can exert a variety of direct anti-tumor effects, including down-regulation of oncogenes, up-regulation of tumor suppressors, enhancement of immune recognition via increased expression of tumor surface MHC class I proteins, potentiation of apoptosis, and sensitization to chemotherapeutic agents (Gutterman et al., 1994, PNAS USA 91:1198-205; Matarrese et al., 2002, Am J Pathol 160:1507-20; Mecchia et al., 2000, Gene Ther 7:167-79; Sabaawy et al., 1999, Int J Oncol 14:1143-51; Takaoka et al, 2003, Nature 424:516-23). For some tumors, IFNα can have a direct and potent anti-proliferative effect through activation of STAT1 (Grimley et al., 1998 Blood 91:3017-27). Interferon-α2b has been conjugated to anti-tumor antibodies, such as the hL243 anti-HLA-DR antibody and depletes lymphoma and myeloma cells in vitro and in vivo (Rossi et al., 2011, Blood 118:1877-84).

Indirectly, IFNα can inhibit angiogenesis (Sidky and Borden, 1987, Cancer Res 47:5155-61) and stimulate host immune cells, which may be vital to the overall antitumor response but has been largely under-appreciated (Belardelli et al., 1996, Immunol Today 17:369-72). IFNα has a pleiotropic influence on immune responses through effects on myeloid cells (Raefsky et al, 1985, J Immunol 135:2507-12; Luft et al, 1998, J Immunol 161:1947-53), T-cells (Carrero et al, 2006, J Exp Med 203:933-40; Pilling et al., 1999, Eur J Immunol 29:1041-50), and B-cells (Le et al, 2001, Immunity 14:461-70). As an important modulator of the innate immune system, IFNα induces the rapid differentiation and activation of dendritic cells (Belardelli et al, 2004, Cancer Res 64:6827-30; Paquette et al., 1998, J Leukoc Biol 64:358-67; Santini et al., 2000, J Exp Med 191:1777-88) and enhances the cytotoxicity, migration, cytokine production and antibody-dependent cellular cytotoxicity (ADCC) of NK cells (Biron et al., 1999, Ann Rev Immunol 17:189-220; Brunda et al. 1984, Cancer Res 44:597-601).

Interferon-β has been reported to be efficacious for therapy of a variety of solid tumors. Patients treated with 6 million units of IFN-β twice a week for 36 months showed a decreased recurrence of hepatocellular carcinoma after complete resection or ablation of the primary tumor in patients with HCV-related liver cancer (Ikeda et al., 2000, Hepatology 32:228-32). Gene therapy with interferon-β induced apoptosis of glioma, melanoma and renal cell carcinoma (Yoshida et al., 2004, Cancer Sci 95:858-65). Endogenous IFN-β has been observed to inhibit tumor growth by inhibiting angiogenesis in vivo (Jablonska et al., 2010, J Clin Invest. 120:1151-64.)

The therapeutic effectiveness of IFNs has been validated to date by the approval of IFN-α2 for treating hairy cell leukemia, chronic myelogenous leukemia, malignant melanoma, follicular lymphoma, condylomata acuminata, AIDs-related Kaposi sarcoma, and chronic hepatitis B and C; IFN-β for treating multiple sclerosis; and IFN-γ for treating chronic granulomatous disease and malignant osteopetrosis. Despite a vast literature on this group of autocrine and paracrine cytokines, their functions in health and disease are still being elucidated, including more effective and novel forms being introduced clinically (Pestka, 2007, J. Biol. Chem 282:20047-51; Vilcek, 2006, Immunity 25:343-48).

Interferons are critical role players in the antitumor and antimicrobial host defense, and have been extensively explored as therapeutic agents for cancer and infectious disease (Billiau et al., 2006, Cytokine Growth Factor Rev 17:381-409; Pestka et al., 2004, Immunol Rev 202:8-32). Despite considerable efforts with type I and II interferons (IFN-α/β and γ), their use in clinic settings have been limited because of the short circulation half-life, systemic toxicity, and suboptimal responses in patients (Pestka et al., 2004, Immunol Rev 202:8-32; Miller et al., 2009, Ann N Y Acad Sci 1182:69-79). The discovery of the IFN-λ family in early 2003 brought an exciting new opportunity to develop alternative IFN agents for these unmet clinical indications (Kotenko et al., 2003, Nat Immunol 4:69-77; Sheppard et al., 2003, Nat Immunol 4:63-8).

IFN-λs, designated as type III interferons, are a newly described group of cytokines that consist of IFN-λ1, 2, 3 (also referred to as interleukin-29, 28A, and 28B, respectively), that are genetically encoded by three different genes located on chromosome 19 (Kotenko et al., 2003, Nat Immunol 4:69-77; Sheppard et al., 2003, Nat Immunol 4:63-8). At the protein level, IFN-λ2 and -λ3 are is highly homologous, with 96% amino acid identity, while IFN-λ1 shares approximately 81% homology with IFN-λ2 and -λ3 (Sheppard et al., 2003, Nat Immunol 4:63-8). IFN-λs activate signal transduction via the JAK/STAT pathway similar to that induced by type I IFN, including the activation of JAK1 and TYK2 kinases, the phosphorylation of STAT proteins, and the activation of the transcription complex of IFN-stimulated gene factor 3 (ISGF3) (Witte et al., 2010, Cytokine Growth Factor Rev 21:237-51; Zhou et al., 2007, J Virol 81:7749-58).

A major difference between type III and type I IFN systems is the distribution of their respective receptor complexes. IFN-α/β signals through two extensively expressed type I interferon receptors, and the resulting systemic toxicity associated with IFN-α/β administration has limited their use as therapeutic agents (Pestka et al., 2007, J Biol Chem 282:20047-51). In contrast, IFN-λs signal through a heterodimeric receptor complex consisting of unique IFN-λ, receptor 1 (IFN-λR1) and IL-10 receptor 2 (IL-10R2). As previously reported (Witte et al., 2009, Genes Immun 10:702-14), IFN-λR1 has a very restricted expression pattern with the highest levels in epithelial cells, melanocytes, and hepatocytes, and the lowest level in primary central nervous system (CNS) cells. Blood immune system cells express high levels of a short IFN-λ, receptor splice variant (sIFN-λR1) that inhibits IFN-λ, action. The limited responsiveness of neuronal cells and immune cells implies that the severe toxicity frequently associated with IFN-α therapy may be absent or significantly reduced with IFN-λs (Witte et al., 2009, Genes Immun 10:702-14; Witte et al., 2010, Cytokine Growth Factor Rev 21:237-51). A recent publication reported that while IFN-α and IFN-λ, induce expression of a common set of ISGs (interferon-stimulated genes) in hepatocytes, unlike IFN-α, administration of IFN-λ, did not induce STAT activation or ISG expression in purified lymphocytes or monocytes (Dickensheets et al., 2013, J Leukoc Biol. 93, published online Dec. 20, 2012). It was suggested that IFN-λ, may be superior to IFN-α for treatment of chronic HCV infection, as it is less likely to induce leukopenias that are often associated with IFN-α therapy (Dickensheets et al., 2013).

IFN-λs display structural features similar to IL-10-related cytokines, but functionally possess type I IFN-like anti-viral and anti-proliferative activity (Witte et al., 2009, Genes Immun 10:702-14; Ank et al., 2006, J Virol 80:4501-9; Robek et al., 2005, J Virol 79:3851-4). IFN-λ1 and -λ2 have been demonstrated to reduce viral replication or the cytopathic effect of various viruses, including DNA viruses (hepatitis B virus (Robek et al., 2005, J Virol 79:3851-4, Doyle et al., 2006, Hepatology 44:896-906) and herpes simplex virus 2 (Ank et al., 2008, J Immunol 180:2474-85)), ss (+) RNA viruses (EMCV; Sheppard et al., 2003, Nat Immunol 4:63-8) and hepatitis C virus (Robek et al., 2005, J Virol 79:3851-4, Doyle et al., 2006, Hepatology 44:896-906; Marcello et al., 2006, Gastroenterol 131:1887-98; Pagliaccetti et al., 2008, J Biol Chem 283:30079-89), ss (−) RNA viruses (vesicular stomatitis virus; Pagliaccetti et al., 2008, J Biol Chem 283:30079-89) and influenza-A virus (Jewell et al., 2010, J Virol 84:11515-22) and double-stranded RNA viruses, such as rotavirus (Pott et al., 2011, PNAS USA 108:7944049). IFN-λ3 has been identified from genetic studies as a key cytokine in HCV infection (Ge et al., 2009, Nature 461:399-401), and has also shown potent activity against EMCV (Dellgren et al., 2009, Genes Immun 10:125-31). A deficiency of rhinovirus-induced IFN-λ, production was reported to be highly correlated with the severity of rhinovirus-induced asthma exacerbation (Contoli et al., 2006, Nature Med 12:1023-26) and IFN-λ, therapy has been suggested as a new approach for treatment of allergic asthma (Edwards and Johnston, 2011, EMBO Mol Med 3:306-8; Koltsida et al., 2011, EMBO Mol Med 3:348-61).

The anti-proliferative activity of IFN-λs has been established in several human cancer cell lines, including neuroendocrine carcinoma BON1 (Zitzmann et al., 2006, Biochem Biophys Res Commun 344:1334-41), glioblastoma LN319 (Meager et al., 2005, Cytokine 31:109-18), immortalized keratinocyte HaCaT (Maher et al., 2008, Cancer Biol Ther 7:1109-15), melanoma F01 (Guenterberg et al., 2010, Mol Cancer Ther 9:510-20), and esophageal carcinoma TE-11 (Li et al., 2010, Eur J Cancer 46:180-90). In animal models, IFN-λs induce both tumor apoptosis and destruction through innate and adaptive immune responses, suggesting that local delivery of IFN-λ, might be a useful adjunctive strategy in the treatment of human malignancies (Numasaki et al., 2007, J Immunol 178:5086-98).

In clinical settings, PEGylated IFN-λ1 (PEG-IFN-λ1) has been provisionally used for patients with chronic hepatitis C virus infection. In a phase Ib study (n=56), antiviral activity was observed at all dose levels (0.5-3.0 μg/kg), and viral load reduced 2.3 to 4.0 logs when PEG-IFN-λ1 was administrated to genotype 1 HCV patients who relapsed after IFN-α therapy (Muir et al., 2010, Hepatology 52:822-32). A phase IIb study (n=526) showed that patients with HCV genotypes 1 and 4 had significantly higher response rates to treatment with PEG-IFN-λ1 compared to PEG-IFN-α. At the same time, rates of adverse events commonly associated with type I interferon treatment were lower with PEG-IFN-λ1 than with PEG-IFN-α. Neutropenia and thrombocytopenia were infrequently observed and the rates of flu-like symptoms, anemia, and musculoskeletal symptoms decreased to about ⅓ of that seen with PEG-IFN-α treatment. However, rates of serious adverse events, depression and other common adverse events (>10%) were similar between PEG-IFN-λ1 and PEG-IFN-α. Higher rates of hepatotoxicity were seen in the highest-dose PEG-IFN-λ1 compared with PEG-IFN-α (“Investigational Compound PEG-Interferon Lambda Achieved Higher Response Rates with Fewer Flu-like and Musculoskeletal Symptoms and Cytopenias Than PEG-Interferon Alfa in Phase IIb Study of 526 Treatment-Naive Hepatitis C Patients,” Apr. 2, 2011, Press Release from Bristol-Myers Squibb).

In various embodiments, the subject T-cell redirecting bispecific antibodies may be used in combination with one or more interferons, such as interferon-α, interferon-β, interferon-λ1, interferon-λ2, or interferon-λ3. When used with the subject bsAbs, the interferon may be administered prior to, concurrently with, or after the bsAb. When administered concurrently, the interferon may be either conjugated to or separate from the bsAb.

T-Cell Redirecting Bispecific Antibody Complexes

Various embodiments concern bsAbs comprising an anti-CD3 antibody or fragment thereof attached to an antibody or fragment thereof against a disease-associated antigen, such as CD19. Bispecific anti-CD3×anti-CD19 antibodies are known in the art and are presently in clinical development, such as BITE® (Bispecific T-cell Engager) (e.g., Nagorsen et al., 2009, Leukemia & Lymphoma 50:886-91; Amann et al., 2009, J Immunother 32:453-64; Baeuerle and Reinhardt, 2009, Cancer Res 69:4941-44) and DART® (see, e.g., Moore et al., 2011, Blood 117:4542-51; Veri et al., 2010, Arthritis Rheum 62:1933-43).

Blinatumomab is a BITE® antibody comprising V_(H) and V_(L) domains of anti-CD3 and anti-CD19 antibody fragments, connected with a 5-amino acid linker and expressed as a single polypeptide chain that anneals to itself to form the antigen-binding sites. It is thought that blinatumomab acts by bringing the T-cell-specific CD3 and B-cell specific CD19 antigens into close proximity, to initiate a T-cell cytotoxic response against the juxtaposed B cells, which does not require T-cell specificity to the cancer cells (e.g., Portell et al., 2013, Clin Pharmacol 5(Suppl 1): 5-11). Due to its short half-life, blinatumomab requires continuous intravenous infusion to be effective, (Portell et al., 2013). A phase II trial of B-cell ALL patients with persistent or relapsed minimal residual disease reported an approximately 80% rate of complete remission (Portell et al., 2013).

Doses of blinatumomab as low as 0.005 mg/m²/day were reported to be effective to eliminate cancer cells in non-Hodgkin's lymphoma patients (Bargou et al., 2008, Science 321:974-77). Partial and complete remissions were observed starting at a dose level of 0.015 mg and all six patients tested at a dose of 0.06 mg experienced a tumor regression (Bargou et al., 2008). In vitro, blinatumomab induced 50% cell lysis of MEC-1 cells at a concentration of 10 pg/mL (Topp et al., 2012, Blood 120:5185-87; Bassan et al., 2012, Blood 120:5094-95).

The anti-CD19 portion of blinatumomab was derived from the HD37 hybridoma (see, e.g., U.S. Pat. No. 7,575,923, the Examples section of which is incorporated herein by reference), which is publicly available (e.g., Santa Cruz Biotechnology Cat. No. sc-18894). The anti-CD3 portion of blinatumomab was derived from the TR66 hybridoma (U.S. Pat. No. 7,575,923; Traunecker et al., 1991, EMBO J. 10:3655-59), also publicly available (e.g., Enzo Life Sciences, catalog No. ALX-804-822-C100).

A variety of antibodies against CD3 that may be used in the claimed methods and compositions are publicly known and/or commercially available, such as from LSBio (catalog Nos. LS-B6698, LS-B8669; LS-B8765, LS-C96311, LS-058677, etc.); ABCAM® (catalog Nos. ab5690, ab16669, ab699, ab828, ab8671, etc.); Santa Cruz Biotechnology (catalog Nos.sc-20047, sc-20080, sc-19590, sc-59008, sc-101442, etc.); and many other suppliers.

In a preferred embodiment, the amino acid sequence of the anti-CD3 moiety, used as part of a DNL™ complex, is as disclosed below in SEQ ID NO:96 to SEQ ID NO:101. However, the person of ordinary skill will realize that any known anti-CD3 antibody may be utilized in the claimed methods and compositions. Preferably, the antibody moieties of use are humanized or human.

A variety of antibodies against CD19 that may be used in the claimed methods and compositions are publicly known and/or commercially available, such as from Santa Cruz Biotechnology (catalog Nos. sc-390244, sc-373897, sc-18894, sc-18896, etc.); ABCAM® (catalog Nos. ab25232, ab134114, ab140981, ab1255, etc.); ABBIOTEC™ (catalog Nos. 252262, 252248, 250585, 251063, etc.) and many other vendors.

In a preferred embodiment, the anti-CD19 antibody moiety is a humanized A19 antibody, comprising the light chain CDR sequences CDR1 KASQSVDYDGDSYLN (SEQ ID NO:90); CDR2 DASNLVS (SEQ ID NO:91); and CDR3 QQSTEDPWT (SEQ ID NO:92) and the heavy chain CDR sequences CDR1 SYWMN (SEQ ID NO:93); CDR2 QIWPGDGDTNYNGKFKG (SEQ ID NO:94) and CDR3 RETTTVGRYYYAMDY (SEQ ID NO:95).

Other anti-CD3×anti-CD19 bispecific antibodies are known, such as DART®, which also incorporates the anti-CD19 Fv sequences of HD37 and the anti-CD3 Fv sequences of TR66 (Moore et al., 2011, Blood 117:4542-51; Veri et al., 2010, Arthritis Rheum 62:1933-43). Moore et al. (2011) reported that DART® bispecific antibodies were more potent at inducing B cell lysis than single-chain, bispecific antibodies (BITE®) bearing identical anti-CD19 and anti-CD3 variable region sequences, with EC₅₀ values in the pg/mL range (Moore et al., 2011). Other anti-CD3×anti-CD19 bispecific antibodies besides DART® and BITE® have been reported (see, e.g., Wei et al., 2012, Cell Oncol 35:423-34; Portner et al., 2012, Cancer Immunol Immunother 61:1869-75; Zhou et al., 2012, Biotechnol Lett. 34:1183-91). In certain embodiments, any known anti-CD3×anti-CD19 bispecific antibody may be used to induce an immune response against disease-associated cells or pathogens.

In a most preferred embodiment, the anti-CD3×anti-CD19 bispecific antibody is made as a DNL™ construct, as disclosed in Example 1 below. The person of ordinary skill will realize that the subject T-cell redirecting bispecific antibodies are not limited to anti-CD3×anti-CD19 constructs, but may comprise antibodies against any known disease-associated antigens attached to an anti-CD3 antibody moiety.

General Antibody Techniques

Techniques for preparing monoclonal antibodies against virtually any target antigen are well known in the art. See, for example, Kohler and Milstein, Nature 256: 495 (1975), and Coligan et al. (eds.), CURRENT PROTOCOLS IN IMMUNOLOGY, VOL. 1, pages 2.5.1-2.6.7 (John Wiley & Sons 1991). Briefly, monoclonal antibodies can be obtained by injecting mice with a composition comprising an antigen, removing the spleen to obtain B-lymphocytes, fusing the B-lymphocytes with myeloma cells to produce hybridomas, cloning the hybridomas, selecting positive clones which produce antibodies to the antigen, culturing the clones that produce antibodies to the antigen, and isolating the antibodies from the hybridoma cultures.

MAbs can be isolated and purified from hybridoma cultures by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein-A Sepharose, size-exclusion chromatography, and ion-exchange chromatography. See, for example, Coligan at pages 2.7.1-2.7.12 and pages 2.9.1-2.9.3. Also, see Baines et al., “Purification of Immunoglobulin G (IgG),” in METHODS IN MOLECULAR BIOLOGY, VOL. 10, pages 79-104 (The Humana Press, Inc. 1992).

After the initial raising of antibodies to the immunogen, the antibodies can be sequenced and subsequently prepared by recombinant techniques. Humanization and chimerization of murine antibodies and antibody fragments are well known to those skilled in the art. The use of antibody components derived from humanized, chimeric or human antibodies obviates potential problems associated with the immunogenicity of murine constant regions.

Chimeric Antibodies

A chimeric antibody is a recombinant protein in which the variable regions of a human antibody have been replaced by the variable regions of, for example, a mouse antibody, including the complementarity-determining regions (CDRs) of the mouse antibody. Chimeric antibodies exhibit decreased immunogenicity and increased stability when administered to a subject. General techniques for cloning murine immunoglobulin variable domains are disclosed, for example, in Orlandi et al., Proc. Nat'l Acad. Sci. USA 86: 3833 (1989). Techniques for constructing chimeric antibodies are well known to those of skill in the art. As an example, Leung et al., Hybridoma 13:469 (1994), produced an LL2 chimera by combining DNA sequences encoding the V_(κ) and V_(H) domains of murine LL2, an anti-CD22 monoclonal antibody, with respective human κ and IgG₁ constant region domains.

Humanized Antibodies

Techniques for producing humanized MAbs are well known in the art (see, e.g., Jones et al., Nature 321: 522 (1986), Riechmann et al., Nature 332: 323 (1988), Verhoeyen et al., Science 239: 1534 (1988), Carter et al., Proc. Nat'l Acad. Sci. USA 89: 4285 (1992), Sandhu, Crit. Rev. Biotech. 12: 437 (1992), and Singer et al., J. Immun. 150: 2844 (1993)). A chimeric or murine monoclonal antibody may be humanized by transferring the mouse CDRs from the heavy and light variable chains of the mouse immunoglobulin into the corresponding variable domains of a human antibody. The mouse framework regions (FR) in the chimeric monoclonal antibody are also replaced with human FR sequences. As simply transferring mouse CDRs into human FRs often results in a reduction or even loss of antibody affinity, additional modification might be required in order to restore the original affinity of the murine antibody. This can be accomplished by the replacement of one or more human residues in the FR regions with their murine counterparts to obtain an antibody that possesses good binding affinity to its epitope. See, for example, Tempest et al., Biotechnology 9:266 (1991) and Verhoeyen et al., Science 239: 1534 (1988). Generally, those human FR amino acid residues that differ from their murine counterparts and are located close to or touching one or more CDR amino acid residues would be candidates for substitution.

Human Antibodies

Methods for producing fully human antibodies using either combinatorial approaches or transgenic animals transformed with human immunoglobulin loci are known in the art (e.g., Mancini et al., 2004, New Microbiol. 27:315-28; Conrad and Scheller, 2005, Comb. Chem. High Throughput Screen. 8:117-26; Brekke and Loset, 2003, Curr. Opin. Phamacol. 3:544-50). A fully human antibody also can be constructed by genetic or chromosomal transfection methods, as well as phage display technology, all of which are known in the art. See for example, McCafferty et al., Nature 348:552-553 (1990). Such fully human antibodies are expected to exhibit even fewer side effects than chimeric or humanized antibodies and to function in vivo as essentially endogenous human antibodies. In certain embodiments, the claimed methods and procedures may utilize human antibodies produced by such techniques.

In one alternative, the phage display technique may be used to generate human antibodies (e.g., Dantas-Barbosa et al., 2005, Genet. Mol. Res. 4:126-40). Human antibodies may be generated from normal humans or from humans that exhibit a particular disease state, such as cancer (Dantas-Barbosa et al., 2005). The advantage to constructing human antibodies from a diseased individual is that the circulating antibody repertoire may be biased towards antibodies against disease-associated antigens.

In one non-limiting example of this methodology, Dantas-Barbosa et al. (2005) constructed a phage display library of human Fab antibody fragments from osteosarcoma patients. Generally, total RNA was obtained from circulating blood lymphocytes (Id.). Recombinant Fab were cloned from the μ, γ and κ chain antibody repertoires and inserted into a phage display library (Id.). RNAs were converted to cDNAs and used to make Fab cDNA libraries using specific primers against the heavy and light chain immunoglobulin sequences (Marks et al., 1991, J. Mol. Biol. 222:581-97). Library construction was performed according to Andris-Widhopf et al. (2000, In: PHAGE DISPLAY LABORATORY MANUAL, Barbas et al. (eds), 1^(st) edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. pp. 9.1 to 9.22). The final Fab fragments were digested with restriction endonucleases and inserted into the bacteriophage genome to make the phage display library. Such libraries may be screened by standard phage display methods, as known in the art (see, e.g., Pasqualini and Ruoslahti, 1996, Nature 380:364-366; Pasqualini, 1999, The Quart. J. Nucl. Med. 43:159-162).

Phage display can be performed in a variety of formats, for their review, see e.g. Johnson and Chiswell, Current Opinion in Structural Biology 3:5564-571 (1993). Human antibodies may also be generated by in vitro activated B cells. See U.S. Pat. Nos. 5,567,610 and 5,229,275, incorporated herein by reference in their entirety. The skilled artisan will realize that these techniques are exemplary and any known method for making and screening human antibodies or antibody fragments may be utilized.

In another alternative, transgenic animals that have been genetically engineered to produce human antibodies may be used to generate antibodies against essentially any immunogenic target, using standard immunization protocols. Methods for obtaining human antibodies from transgenic mice are disclosed by Green et al., Nature Genet. 7:13 (1994), Lonberg et al., Nature 368:856 (1994), and Taylor et al., Int. Immun. 6:579 (1994). A non-limiting example of such a system is the XENOMOUSE® (e.g., Green et al., 1999, J. Immunol. Methods 231:11-23) from Abgenix (Fremont, Calif.). In the XENOMOUSE® and similar animals, the mouse antibody genes have been inactivated and replaced by functional human antibody genes, while the remainder of the mouse immune system remains intact.

The XENOMOUSE® was transformed with germline-configured YACs (yeast artificial chromosomes) that contained portions of the human IgH and Igkappa loci, including the majority of the variable region sequences, along accessory genes and regulatory sequences. The human variable region repertoire may be used to generate antibody producing B cells, which may be processed into hybridomas by known techniques. A XENOMOUSE® immunized with a target antigen will produce human antibodies by the normal immune response, which may be harvested and/or produced by standard techniques discussed above. A variety of strains of XENOMOUSE® are available, each of which is capable of producing a different class of antibody. Transgenically produced human antibodies have been shown to have therapeutic potential, while retaining the pharmacokinetic properties of normal human antibodies (Green et al., 1999). The skilled artisan will realize that the claimed compositions and methods are not limited to use of the XENOMOUSE® system but may utilize any transgenic animal that has been genetically engineered to produce human antibodies.

Antibody Cloning and Production

Various techniques, such as production of chimeric or humanized antibodies, may involve procedures of antibody cloning and construction. The antigen-binding Vκ (variable light chain) and V_(H) (variable heavy chain) sequences for an antibody of interest may be obtained by a variety of molecular cloning procedures, such as RT-PCR, 5′-RACE, and cDNA library screening. The V genes of an antibody from a cell that expresses a murine antibody can be cloned by PCR amplification and sequenced. To confirm their authenticity, the cloned V_(L) and V_(H) genes can be expressed in cell culture as a chimeric Ab as described by Orlandi et al., (Proc. Natl. Acad. Sci. USA, 86: 3833 (1989)). Based on the V gene sequences, a humanized antibody can then be designed and constructed as described by Leung et al. (Mol. Immunol., 32: 1413 (1995)).

cDNA can be prepared from any known hybridoma line or transfected cell line producing a murine antibody by general molecular cloning techniques (Sambrook et al., Molecular Cloning, A laboratory manual, 2^(nd) Ed (1989)). The Vκ sequence for the antibody may be amplified using the primers VK1BACK and VK1FOR (Orlandi et al., 1989) or the extended primer set described by Leung et al. (BioTechniques, 15: 286 (1993)). The V_(H) sequences can be amplified using the primer pair VH1BACK/VH1FOR (Orlandi et al., 1989) or the primers annealing to the constant region of murine IgG described by Leung et al. (Hybridoma, 13:469 (1994)). Humanized V genes can be constructed by a combination of long oligonucleotide template syntheses and PCR amplification as described by Leung et al. (Mol. Immunol., 32: 1413 (1995)).

PCR products for Vκ can be subcloned into a staging vector, such as a pBR327-based staging vector, VKpBR, that contains an Ig promoter, a signal peptide sequence and convenient restriction sites. PCR products for V_(H) can be subcloned into a similar staging vector, such as the pBluescript-based VHpBS. Expression cassettes containing the Vκ and V_(H) sequences together with the promoter and signal peptide sequences can be excised from VKpBR and VHpBS and ligated into appropriate expression vectors, such as pKh and pG1g, respectively (Leung et al., Hybridoma, 13:469 (1994)). The expression vectors can be co-transfected into an appropriate cell and supernatant fluids monitored for production of a chimeric, humanized or human antibody. Alternatively, the Vκ and V_(H) expression cassettes can be excised and subcloned into a single expression vector, such as pdHL2, as described by Gillies et al. (J. Immunol. Methods 125:191 (1989) and also shown in Losman et al., Cancer, 80:2660 (1997)).

In an alternative embodiment, expression vectors may be transfected into host cells that have been pre-adapted for transfection, growth and expression in serum-free medium. Exemplary cell lines that may be used include the Sp/EEE, Sp/ESF and Sp/ESF-X cell lines (see, e.g., U.S. Pat. Nos. 7,531,327; 7,537,930 and 7,608,425; the Examples section of each of which is incorporated herein by reference). These exemplary cell lines are based on the Sp2/0 myeloma cell line, transfected with a mutant Bcl-EEE gene, exposed to methotrexate to amplify transfected gene sequences and pre-adapted to serum-free cell line for protein expression.

Antibody Fragments

Antibody fragments which recognize specific epitopes can be generated by known techniques. Antibody fragments are antigen binding portions of an antibody, such as F(ab′)₂, Fab′, F(ab)₂, Fab, Fv, scFv and the like. F(ab′)₂ fragments can be produced by pepsin digestion of the antibody molecule and Fab′ fragments can be generated by reducing disulfide bridges of the F(ab′)₂ fragments. Alternatively, Fab′ expression libraries can be constructed (Huse et al., 1989, Science, 246:1274-1281) to allow rapid and easy identification of monoclonal Fab′ fragments with the desired specificity. F(ab)₂ fragments may be generated by papain digestion of an antibody.

A single chain Fv molecule (scFv) comprises a VL domain and a VH domain. The VL and VH domains associate to form a target binding site. These two domains are further covalently linked by a peptide linker (L). Methods for making scFv molecules and designing suitable peptide linkers are described in U.S. Pat. No. 4,704,692; U.S. Pat. No. 4,946,778; Raag and Whitlow, FASEB 9:73-80 (1995) and Bird and Walker, TIBTECH, 9: 132-137 (1991).

Techniques for producing single domain antibodies (DABs or VHH) are also known in the art, as disclosed for example in Cossins et al. (2006, Prot Express Purif 51:253-259), incorporated herein by reference. Single domain antibodies may be obtained, for example, from camels, alpacas or llamas by standard immunization techniques. (See, e.g., Muyldermans et al., TIBS 26:230-235, 2001; Yau et al., J Immunol Methods 281:161-75, 2003; Maass et al., J Immunol Methods 324:13-25, 2007). The VHH may have potent antigen-binding capacity and can interact with novel epitopes that are inaccessible to conventional VH-VL pairs. (Muyldermans et al., 2001). Alpaca serum IgG contains about 50% camelid heavy chain only IgG antibodies (HCAbs) (Maass et al., 2007). Alpacas may be immunized with known antigens, such as TNF-α, and VHHs can be isolated that bind to and neutralize the target antigen (Maass et al., 2007). PCR primers that amplify virtually all alpaca VHH coding sequences have been identified and may be used to construct alpaca VHH phage display libraries, which can be used for antibody fragment isolation by standard biopanning techniques well known in the art (Maass et al., 2007). In certain embodiments, anti-pancreatic cancer VHH antibody fragments may be utilized in the claimed compositions and methods.

An antibody fragment can be prepared by proteolytic hydrolysis of the full length antibody or by expression in E. coli or another host of the DNA coding for the fragment. An antibody fragment can be obtained by pepsin or papain digestion of full length antibodies by conventional methods. These methods are described, for example, by Goldenberg, U.S. Pat. Nos. 4,036,945 and 4,331,647 and references contained therein. Also, see Nisonoff et al., Arch Biochem. Biophys. 89: 230 (1960); Porter, Biochem. J. 73: 119 (1959), Edelman et al., in METHODS IN ENZYMOLOGY VOL. 1, page 422 (Academic Press 1967), and Coligan at pages 2.8.1-2.8.10 and 2.10.-2.10.4.

Antibody Allotypes

Immunogenicity of therapeutic antibodies is associated with increased risk of infusion reactions and decreased duration of therapeutic response (Baert et al., 2003, N Engl J Med 348:602-08). The extent to which therapeutic antibodies induce an immune response in the host may be determined in part by the allotype of the antibody (Stickler et al., 2011, Genes and Immunity 12:213-21). Antibody allotype is related to amino acid sequence variations at specific locations in the constant region sequences of the antibody. The allotypes of IgG antibodies containing a heavy chain γ-type constant region are designated as Gm allotypes (1976, J Immunol 117:1056-59).

For the common IgG1 human antibodies, the most prevalent allotype is G1m1 (Stickler et al., 2011, Genes and Immunity 12:213-21). However, the G1m3 allotype also occurs frequently in Caucasians (Stickler et al., 2011). It has been reported that G1m1 antibodies contain allotypic sequences that tend to induce an immune response when administered to non-G1m1 (nG1m1) recipients, such as G1m3 patients (Stickler et al., 2011). Non-G1m1 allotype antibodies are not as immunogenic when administered to G1m1 patients (Stickler et al., 2011).

The human G1m1 allotype comprises the amino acids aspartic acid at Kabat position 356 and leucine at Kabat position 358 in the CH3 sequence of the heavy chain IgG1. The nG1m1 allotype comprises the amino acids glutamic acid at Kabat position 356 and methionine at Kabat position 358. Both G1m1 and nG1m1 allotypes comprise a glutamic acid residue at Kabat position 357 and the allotypes are sometimes referred to as DEL and EEM allotypes. A non-limiting example of the heavy chain constant region sequences for G1m1 and nG1m1 allotype antibodies is shown for the exemplary antibodies rituximab (SEQ ID NO:85) and veltuzumab (SEQ ID NO:86).

Rituximab heavy chain variable region sequence (SEQ ID NO: 85) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKKAEP KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSRDELTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW QQGNVFSCSVMHEALHNHYTQKSLSLSPGK Veltuzumab heavy chain variable region (SEQ ID NO: 86) ASTKGPSVFPLAPSSKSTSGGTAALGCLVKDYFPEPVTVSWNSGALTSGV HTFPAVLQSSGLYSLSSVVTVPSSSLGTQTYICNVNHKPSNTKVDKRVEP KSCDKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVS HEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGK EYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTC LVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTVDKSRW QQGNVFSCSVMHEALHNHYTQKSLSLSPGK

Jefferis and Lefranc (2009, mAbs 1:1-7) reviewed sequence variations characteristic of IgG allotypes and their effect on immunogenicity. They reported that the G1m3 allotype is characterized by an arginine residue at Kabat position 214, compared to a lysine residue at Kabat 214 in the G1m17 allotype. The nG1m1,2 allotype was characterized by glutamic acid at Kabat position 356, methionine at Kabat position 358 and alanine at Kabat position 431. The G1m1,2 allotype was characterized by aspartic acid at Kabat position 356, leucine at Kabat position 358 and glycine at Kabat position 431. In addition to heavy chain constant region sequence variants, Jefferis and Lefranc (2009) reported allotypic variants in the kappa light chain constant region, with the Km1 allotype characterized by valine at Kabat position 153 and leucine at Kabat position 191, the Km1,2 allotype by alanine at Kabat position 153 and leucine at Kabat position 191, and the Km3 allotype characterized by alanine at Kabat position 153 and valine at Kabat position 191.

With regard to therapeutic antibodies, veltuzumab and rituximab are, respectively, humanized and chimeric IgG1 antibodies against CD20, of use for therapy of a wide variety of hematological malignancies and/or autoimmune diseases. Table 1 compares the allotype sequences of rituximab vs. veltuzumab. As shown in Table 1, rituximab (G1m17,1) is a DEL allotype IgG1, with an additional sequence variation at Kabat position 214 (heavy chain CH1) of lysine in rituximab vs. arginine in veltuzumab. It has been reported that veltuzumab is less immunogenic in subjects than rituximab (see, e.g., Morchhauser et al., 2009, J Clin Oncol 27:3346-53; Goldenberg et al., 2009, Blood 113:1062-70; Robak & Robak, 2011, BioDrugs 25:13-25), an effect that has been attributed to the difference between humanized and chimeric antibodies. However, the difference in allotypes between the EEM and DEL allotypes likely also accounts for the lower immunogenicity of veltuzumab.

TABLE 1 Allotypes of Rituximab vs. Veltuzumab Heavy chain position and associated allotypes Complete 214 356/358 431 allotype (allotype) (allotype) (allotype) Rituximab G1m17,1 K 17 D/L 1 A — Veltuzumab G1m3 R 3 E/M — A —

In order to reduce the immunogenicity of therapeutic antibodies in individuals of nG1m1 genotype, it is desirable to select the allotype of the antibody to correspond to the G1m3 allotype, characterized by arginine at Kabat 214, and the nG1m1,2 null-allotype, characterized by glutamic acid at Kabat position 356, methionine at Kabat position 358 and alanine at Kabat position 431. Surprisingly, it was found that repeated subcutaneous administration of G1m3 antibodies over a long period of time did not result in a significant immune response. In alternative embodiments, the human IgG4 heavy chain in common with the G1m3 allotype has arginine at Kabat 214, glutamic acid at Kabat 356, methionine at Kabat 359 and alanine at Kabat 431. Since immunogenicity appears to relate at least in part to the residues at those locations, use of the human IgG4 heavy chain constant region sequence for therapeutic antibodies is also a preferred embodiment. Combinations of G1m3 IgG1 antibodies with IgG4 antibodies may also be of use for therapeutic administration.

Known Antibodies

Target Antigens and Exemplary Antibodies

In a preferred embodiment, antibodies are used that recognize and/or bind to antigens that are expressed at high levels on target cells and that are expressed predominantly or exclusively on diseased cells versus normal tissues. Exemplary antibodies of use for therapy of, for example, cancer include but are not limited to LL1 (anti-CD74), LL2 or RFB4 (anti-CD22), veltuzumab (hA20, anti-CD20), rituxumab (anti-CD20), obinutuzumab (GA101, anti-CD20), lambrolizumab (anti-PD-1 receptor), nivolumab (anti-PD-1 receptor), ipilimumab (anti-CTLA-4), RS7 (anti-epithelial glycoprotein-1 (EGP-1, also known as TROP-2)), PAM4 or KC4 (both anti-mucin), MN-14 (anti-carcinoembryonic antigen (CEA, also known as CD66e or CEACAM5), MN-15 or MN-3 (anti-CEACAM6), Mu-9 (anti-colon-specific antigen-p), Immu 31 (an anti-alpha-fetoprotein), R1 (anti-IGF-1R), A19 (anti-CD19), TAG-72 (e.g., CC49), Tn, J591 or HuJ591 (anti-PSMA (prostate-specific membrane antigen)), AB-PG1-XG1-026 (anti-PSMA dimer), D2/B (anti-PSMA), G250 (an anti-carbonic anhydrase IX MAb), L243 (anti-HLA-DR) alemtuzumab (anti-CD52), bevacizumab (anti-VEGF), cetuximab (anti-EGFR), gemtuzumab (anti-CD33), ibritumomab tiuxetan (anti-CD20); panitumumab (anti-EGFR); tositumomab (anti-CD20); PAM4 (aka clivatuzumab, anti-mucin) and trastuzumab (anti-ErbB2). Such antibodies are known in the art (e.g., U.S. Pat. Nos. 5,686,072; 5,874,540; 6,107,090; 6,183,744; 6,306,393; 6,653,104; 6,730,300; 6,899,864; 6,926,893; 6,962,702; 7,074,403; 7,230,084; 7,238,785; 7,238,786; 7,256,004; 7,282,567; 7,300,655; 7,312,318; 7,585,491; 7,612,180; 7,642,239; and U.S. Patent Application Publ. No. 20050271671; 20060193865; 20060210475; 20070087001; the Examples section of each incorporated herein by reference.) Specific known antibodies of use include hPAM4 (U.S. Pat. No. 7,282,567), hA20 (U.S. Pat. No. 7,251,164), hA19 (U.S. Pat. No. 7,109,304), hIMMU-31 (U.S. Pat. No. 7,300,655), hLL1 (U.S. Pat. No. 7,312,318,), hLL2 (U.S. Pat. No. 7,074,403), hMu-9 (U.S. Pat. No. 7,387,773), hL243 (U.S. Pat. No. 7,612,180), hMN-14 (U.S. Pat. No. 6,676,924), hMN-15 (U.S. Pat. No. 7,541,440), hR1 (U.S. patent application Ser. No. 12/772,645), hRS7 (U.S. Pat. No. 7,238,785), hMN-3 (U.S. Pat. No. 7,541,440), AB-PG1-XG1-026 (U.S. patent application Ser. No. 11/983,372, deposited as ATCC PTA-4405 and PTA-4406) and D2/B (WO 2009/130575) the text of each recited patent or application is incorporated herein by reference with respect to the Figures and Examples sections.

Other useful antigens that may be targeted using the described conjugates include carbonic anhydrase IX, B7, CCL19, CCL21, CSAp, HER-2/neu, BrE3, CD1, CD1a, CD2, CD3, CD4, CD5, CD8, CD11A, CD14, CD15, CD16, CD18, CD19, CD20 (e.g., C2B8, hA20, 1F5 MAbs), CD21, CD22, CD23, CD25, CD29, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD44, CD45, CD46, CD52, CD54, CD55, CD59, CD64, CD67, CD70, CD74, CD79a, CD80, CD83, CD95, CD126, CD133, CD138, CD147, CD154, CEACAM5, CEACAM6, CTLA-4, alpha-fetoprotein (AFP), VEGF (e.g., bevacizumab, fibronectin splice variant), ED-B fibronectin (e.g., L19), EGP-1 (TROP-2), EGP-2 (e.g., 17-1A), EGF receptor (ErbB1) (e.g., cetuximab), ErbB2, ErbB3, Factor H, FHL-1, Flt-3, folate receptor, Ga 733, GRO-β, HMGB-1, hypoxia inducible factor (HIF), HM1.24, HER-2/neu, insulin-like growth factor (ILGF), IFN-γ, IFN-α, IFN-β, IFN-k, IL-2R, IL-4R, IL-6R, IL-13R, IL-15R, IL-17R, IL-18R, IL-2, IL-6, IL-8, IL-12, IL-15, IL-17, IL-18, IL-25, IP-10, IGF-1R, Ia, HM1.24, gangliosides, HCG, HLA-DR, CD66 antigens, i.e., CD66a-d or a combination thereof, MAGE, mCRP, MCP-1, MIP-1A, MIP-1B, macrophage migration-inhibitory factor (MIF), MUC1, MUC2, MUC3, MUC4, MUC5ac, placental growth factor (P1GF), PSA (prostate-specific antigen), PSMA, PD-1 receptor, NCA-95, NCA-90, A3, A33, Ep-CAM, KS-1, Le(y), mesothelin, 5100, tenascin, TAC, Tn antigen, Thomas-Friedenreich antigens, tumor necrosis antigens, tumor angiogenesis antigens, TNF-α, TRAIL receptor (R1 and R2), TROP-2, VEGFR, RANTES, T101, as well as cancer stem cell antigens, complement factors C3, C3a, C3b, C5a, C5, and an oncogene product.

A comprehensive analysis of suitable antigen (Cluster Designation, or CD) targets on hematopoietic malignant cells, as shown by flow cytometry and which can be a guide to selecting suitable antibodies for immunotherapy, is Craig and Foon, Blood prepublished online Jan. 15, 2008; DOL 10.1182/blood-2007-11-120535.

The CD66 antigens consist of five different glycoproteins with similar structures, CD66a-e, encoded by the carcinoembryonic antigen (CEA) gene family members, BCG, CGM6, NCA, CGM1 and CEA, respectively. These CD66 antigens (e.g., CEACAM6) are expressed mainly in granulocytes, normal epithelial cells of the digestive tract and tumor cells of various tissues. Also included as suitable targets for cancers are cancer testis antigens, such as NY-ESO-1 (Theurillat et al., Int. J. Cancer 2007; 120(11):2411-7), as well as CD79a in myeloid leukemia (Kozlov et al., Cancer Genet. Cytogenet. 2005; 163(1):62-7) and also B-cell diseases, and CD79b for non-Hodgkin's lymphoma (Poison et al., Blood 110(2):616-623). A number of the aforementioned antigens are disclosed in U.S. Provisional Application Ser. No. 60/426,379, entitled “Use of Multi-specific, Non-covalent Complexes for Targeted Delivery of Therapeutics,” filed Nov. 15, 2002. Cancer stem cells, which are ascribed to be more therapy-resistant precursor malignant cell populations (Hill and Perris, J. Natl. Cancer Inst. 2007; 99:1435-40), have antigens that can be targeted in certain cancer types, such as CD133 in prostate cancer (Maitland et al., Ernst Schering Found. Sympos. Proc. 2006; 5:155-79), non-small-cell lung cancer (Donnenberg et al., J. Control Release 2007; 122 (3):385-91), and glioblastoma (Beier et al., Cancer Res. 2007; 67(9):4010-5), and CD44 in colorectal cancer (Dalerba er al., Proc. Natl. Acad. Sci. USA 2007; 104(24)10158-63), pancreatic cancer (Li et al., Cancer Res. 2007; 67(3):1030-7), and in head and neck squamous cell carcinoma (Prince et al., Proc. Natl. Acad. Sci. USA 2007; 104(3)973-8).

For multiple myeloma therapy, suitable targeting antibodies have been described against, for example, CD38 and CD138 (Stevenson, Mol Med 2006; 12(11-12):345-346; Tassone et al., Blood 2004; 104(12):3688-96), CD74 (Stein et al., ibid.), CS1 (Tai et al., Blood 2008; 112(4):1329-37, and CD40 (Tai et al., 2005; Cancer Res. 65(13):5898-5906).

Macrophage migration inhibitory factor (MIF) is an important regulator of innate and adaptive immunity and apoptosis. It has been reported that CD74 is the endogenous receptor for MIF (Leng et al., 2003, J Exp Med 197:1467-76). The therapeutic effect of antagonistic anti-CD74 antibodies on MIF-mediated intracellular pathways may be of use for treatment of a broad range of disease states, such as cancers of the bladder, prostate, breast, lung, colon and chronic lymphocytic leukemia (e.g., Meyer-Siegler et al., 2004, BMC Cancer 12:34; Shachar & Haran, 2011, Leuk Lymphoma 52:1446-54); autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus (Morand & Leech, 2005, Front Biosci 10:12-22; Shachar & Haran, 2011, Leuk Lymphoma 52:1446-54); kidney diseases such as renal allograft rejection (Lan, 2008, Nephron Exp Nephrol. 109:e79-83); and numerous inflammatory diseases (Meyer-Siegler et al., 2009, Mediators Inflamm epub Mar. 22, 2009; Takahashi et al., 2009, Respir Res 10:33. Milatuzumab (hLL1) is an exemplary anti-CD74 antibody of therapeutic use for treatment of MIF-mediated diseases.

Anti-TNF-α antibodies are known in the art and may be of use to treat immune diseases, such as autoimmune disease, immune dysfunction (e.g., graft-versus-host disease, organ transplant rejection) or diabetes. Known antibodies against TNF-α include the human antibody CDP571 (Ofei et al., 2011, Diabetes 45:881-85); murine antibodies MTNFAI, M2TNFAI, M3TNFAI, M3TNFABI, M302B and M303 (Thermo Scientific, Rockford, Ill.); infliximab (Centocor, Malvern, Pa.); certolizumab pegol (UCB, Brussels, Belgium); and adalimumab (Abbott, Abbott Park, Ill.). These and many other known anti-TNF-α antibodies may be used in the claimed methods and compositions. Other antibodies of use for therapy of immune dysregulatory or autoimmune disease include, but are not limited to, anti-B-cell antibodies such as veltuzumab, epratuzumab, milatuzumab or hL243; tocilizumab (anti-IL-6 receptor); basiliximab (anti-CD25); daclizumab (anti-CD25); efalizumab (anti-CD11a); muromonab-CD3 (anti-CD3 receptor); anti-CD40L (UCB, Brussels, Belgium); natalizumab (anti-α4 integrin) and omalizumab (anti-IgE).

Type-1 and Type-2 diabetes may be treated using known antibodies against B-cell antigens, such as CD22 (epratuzumab and hRFB4), CD74 (milatuzumab), CD19 (hA19), CD20 (veltuzumab) or HLA-DR (hL243) (see, e.g., Winer et al., 2011, Nature Med 17:610-18).

The pharmaceutical composition of the present invention may be used to treat a subject having a metabolic disease, such amyloidosis, or a neurodegenerative disease, such as Alzheimer's disease. Bapineuzumab is in clinical trials for Alzheimer's disease therapy. Other antibodies proposed for therapy of Alzheimer's disease include Alz 50 (Ksiezak-Reding et al., 1987, J Biol Chem 263:7943-47), gantenerumab, and solanezumab. Infliximab, an anti-TNF-α antibody, has been reported to reduce amyloid plaques and improve cognition.

In a preferred embodiment, diseases that may be treated using the claimed compositions and methods include cardiovascular diseases, such as fibrin clots, atherosclerosis, myocardial ischemia and infarction. Antibodies to fibrin (e.g., scFv(59D8); T2G1s; MH1) are known and in clinical trials as imaging agents for disclosing said clots and pulmonary emboli, while anti-granulocyte antibodies, such as MN-3, MN-15, anti-NCA95, and anti-CD15 antibodies, can target myocardial infarcts and myocardial ischemia. (See, e.g., U.S. Pat. Nos. 5,487,892; 5,632,968; 6,294,173; 7,541,440, the Examples section of each incorporated herein by reference) Anti-macrophage, anti-low-density lipoprotein (LDL), anti-MIF, and anti-CD74 (e.g., hLL1) antibodies can be used to target atherosclerotic plaques. Abciximab (anti-glycoprotein IIb/IIIa) has been approved for adjuvant use for prevention of restenosis in percutaneous coronary interventions and the treatment of unstable angina (Waldmann et al., 2000, Hematol 1:394-408). Antibodies against oxidized LDL induced a regression of established atherosclerosis in a mouse model (Ginsberg, 2007, J Am Coll Cardiol 52:2319-21). Anti-ICAM-1 antibody was shown to reduce ischemic cell damage after cerebral artery occlusion in rats (Zhang et al., 1994, Neurology 44:1747-51). Commercially available monoclonal antibodies to leukocyte antigens are represented by: OKT anti-T-cell monoclonal antibodies (available from Ortho Pharmaceutical Company) which bind to normal T-lymphocytes; the monoclonal antibodies produced by the hybridomas having the ATCC accession numbers HB44, HB55, HB12, HB78 and HB2; G7E11, W8E7, NKP15 and G022 (Becton Dickinson); NEN9.4 (New England Nuclear); and FMC11 (Sera Labs). A description of antibodies against fibrin and platelet antigens is contained in Knight, Semin. Nucl. Med., 20:52-67 (1990).

An example of a most-preferred antibody/antigen pair is LL1, an anti-CD74 MAb (invariant chain, class II-specific chaperone, Ii) (see, e.g., U.S. Pat. Nos. 6,653,104; 7,312,318; the Examples section of each incorporated herein by reference). The CD74 antigen is highly expressed on B-cell lymphomas (including multiple myeloma) and leukemias, certain T-cell lymphomas, melanomas, colonic, lung, and renal cancers, glioblastomas, and certain other cancers (Ong et al., Immunology 98:296-302 (1999)). A review of the use of CD74 antibodies in cancer is contained in Stein et al., Clin Cancer Res. 2007 Sep. 15; 13(18 Pt 2):55565-5563s, incorporated herein by reference. The diseases that are preferably treated with anti-CD74 antibodies include, but are not limited to, non-Hodgkin's lymphoma, Hodgkin's disease, melanoma, lung, renal, colonic cancers, glioblastome multiforme, histiocytomas, myeloid leukemias, and multiple myeloma.

In another preferred embodiment, the therapeutic conjugates can be used against pathogens, since antibodies against pathogens are known. For example, antibodies and antibody fragments which specifically bind markers produced by or associated with infectious lesions, including viral, bacterial, fungal and parasitic infections, for example caused by pathogens such as bacteria, rickettsia, mycoplasma, protozoa, fungi, and viruses, and antigens and products associated with such microorganisms have been disclosed, inter alia, in Hansen et al., U.S. Pat. No. 3,927,193 and Goldenberg U.S. Pat. Nos. 4,331,647, 4,348,376, 4,361,544, 4,468,457, 4,444,744, 4,818,709 and 4,624,846, the Examples section of each incorporated herein by reference, and in Reichert and Dewitz, cited above. A review listing antibodies against infectious organisms (antitoxin and antiviral antibodies), as well as other targets, is contained in Casadevall, Clin Immunol 1999; 93(1):5-15, incorporated herein by reference.

In a preferred embodiment, the pathogens are selected from the group consisting of HIV virus, Mycobacterium tuberculosis, Streptococcus agalactiae, methicillin-resistant Staphylococcus aureus, Legionella pneumophilia, Streptococcus pyogenes, Escherichia coli, Neisseria gonorrhoeae, Neisseria meningitidis, Pneumococcus, Cryptococcus neoformans, Histoplasma capsulatum, Hemophilis influenzae B, Treponema pallidum, Lyme disease spirochetes, Pseudomonas aeruginosa, Mycobacterium leprae, Brucella abortus, rabies virus, influenza virus, cytomegalovirus, herpes simplex virus I, herpes simplex virus II, human serum parvo-like virus, respiratory syncytial virus, varicella-zoster virus, hepatitis B virus, hepatitis C virus, measles virus, adenovirus, human T-cell leukemia viruses, Epstein-Barr virus, murine leukemia virus, mumps virus, vesicular stomatitis virus, sindbis virus, lymphocytic choriomeningitis virus, wart virus, blue tongue virus, Sendai virus, feline leukemia virus, reovirus, polio virus, simian virus 40, mouse mammary tumor virus, dengue virus, rubella virus, West Nile virus, Plasmodium falciparum, Plasmodium vivax, Toxoplasma gondii, Trypanosoma rangeli, Trypanosoma cruzi, Trypanosoma rhodesiensei, Trypanosoma brucei, Schistosoma mansoni, Schistosoma japonicum, Babesia bovis, Elmeria tenella, Onchocerca volvulus, Leishmania tropica, Trichinella spiralis, Theileria parva, Taenia hydatigena, Taenia ovis, Taenia saginata, Echinococcus granulosus, Mesocestoides corti, Mycoplasma arthritidis, M. hyorhinis, M. orale, M. arginini, Acholeplasma laidlawii, M. salivarium and M. pneumoniae, as disclosed in U.S. Pat. No. 6,440,416, the Examples section of which is incorporated herein by reference.

Antibodies of use to treat autoimmune disease or immune system dysfunctions (e.g., graft-versus-host disease, organ transplant rejection) are known in the art and may be used in the disclosed methods and compositions. Antibodies of use to treat autoimmune/immune dysfunction disease may bind to exemplary antigens including, but not limited to, BCL-1, BCL-2, BCL-6, CD1a, CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD11b, CD11c, CD13, CD14, CD15, CD16, CD19, CD20, CD21, CD22, CD23, CD25, CD33, CD34, CD38, CD40, CD40L, CD41a, CD43, CD45, CD55, TNF-alpha, interferon and HLA-DR. Antibodies that bind to these and other target antigens, discussed above, may be used to treat autoimmune or immune dysfunction diseases. Autoimmune diseases that may be treated with bsAbs may include acute idiopathic thrombocytopenic purpura, chronic idiopathic thrombocytopenic purpura, dermatomyositis, Sydenham's chorea, myasthenia gravis, systemic lupus erythematosus, lupus nephritis, rheumatic fever, polyglandular syndromes, bullous pemphigoid, diabetes mellitus, Henoch-Schonlein purpura, post-streptococcal nephritis, erythema nodosum, Takayasu's arteritis, ANCA-associated vasculitides, Addison's disease, rheumatoid arthritis, multiple sclerosis, sarcoidosis, ulcerative colitis, erythema multiforme, IgA nephropathy, polyarteritis nodosa, ankylosing spondylitis, Goodpasture's syndrome, thromboangitis obliterans, Sjogren's syndrome, primary biliary cirrhosis, Hashimoto's thyroiditis, thyrotoxicosis, scleroderma, chronic active hepatitis, polymyositis/dermatomyositis, polychondritis, bullous pemphigoid, pemphigus vulgaris, Wegener's granulomatosis, membranous nephropathy, amyotrophic lateral sclerosis, tabes dorsalis, giant cell arteritis/polymyalgia, pernicious anemia, rapidly progressive glomerulonephritis, psoriasis or fibrosing alveolitis.

In various embodiments, the claimed methods and compositions may utilize any of a variety of antibodies known in the art. Antibodies of use may be commercially obtained from a number of known sources. For example, a variety of antibody secreting hybridoma lines are available from the American Type Culture Collection (ATCC, Manassas, Va.). A large number of antibodies against various disease targets, including but not limited to tumor-associated antigens, have been deposited at the ATCC and/or have published variable region sequences and are available for use in the claimed methods and compositions. See, e.g., U.S. Pat. Nos. 7,312,318; 7,282,567; 7,151,164; 7,074,403; 7,060,802; 7,056,509; 7,049,060; 7,045,132; 7,041,803; 7,041,802; 7,041,293; 7,038,018; 7,037,498; 7,012,133; 7,001,598; 6,998,468; 6,994,976; 6,994,852; 6,989,241; 6,974,863; 6,965,018; 6,964,854; 6,962,981; 6,962,813; 6,956,107; 6,951,924; 6,949,244; 6,946,129; 6,943,020; 6,939,547; 6,921,645; 6,921,645; 6,921,533; 6,919,433; 6,919,078; 6,916,475; 6,905,681; 6,899,879; 6,893,625; 6,887,468; 6,887,466; 6,884,594; 6,881,405; 6,878,812; 6,875,580; 6,872,568; 6,867,006; 6,864,062; 6,861,511; 6,861,227; 6,861,226; 6,838,282; 6,835,549; 6,835,370; 6,824,780; 6,824,778; 6,812,206; 6,793,924; 6,783,758; 6,770,450; 6,767,711; 6,764,688; 6,764,681; 6,764,679; 6,743,898; 6,733,981; 6,730,307; 6,720,155; 6,716,966; 6,709,653; 6,693,176; 6,692,908; 6,689,607; 6,689,362; 6,689,355; 6,682,737; 6,682,736; 6,682,734; 6,673,344; 6,653,104; 6,652,852; 6,635,482; 6,630,144; 6,610,833; 6,610,294; 6,605,441; 6,605,279; 6,596,852; 6,592,868; 6,576,745; 6,572,856; 6,566,076; 6,562,618; 6,545,130; 6,544,749; 6,534,058; 6,528,625; 6,528,269; 6,521,227; 6,518,404; 6,511,665; 6,491,915; 6,488,930; 6,482,598; 6,482,408; 6,479,247; 6,468,531; 6,468,529; 6,465,173; 6,461,823; 6,458,356; 6,455,044; 6,455,040, 6,451,310; 6,444,206, 6,441,143; 6,432,404; 6,432,402; 6,419,928; 6,413,726; 6,406,694; 6,403,770; 6,403,091; 6,395,276; 6,395,274; 6,387,350; 6,383,759; 6,383,484; 6,376,654; 6,372,215; 6,359,126; 6,355,481; 6,355,444; 6,355,245; 6,355,244; 6,346,246; 6,344,198; 6,340,571; 6,340,459; 6,331,175; 6,306,393; 6,254,868; 6,187,287; 6,183,744; 6,129,914; 6,120,767; 6,096,289; 6,077,499; 5,922,302; 5,874,540; 5,814,440; 5,798,229; 5,789,554; 5,776,456; 5,736,119; 5,716,595; 5,677,136; 5,587,459; 5,443,953, 5,525,338, the Examples section of each of which is incorporated herein by reference. These are exemplary only and a wide variety of other antibodies and their hybridomas are known in the art. The skilled artisan will realize that antibody sequences or antibody-secreting hybridomas against almost any disease-associated antigen may be obtained by a simple search of the ATCC, NCBI and/or USPTO databases for antibodies against a selected disease-associated target of interest. The antigen binding domains of the cloned antibodies may be amplified, excised, ligated into an expression vector, transfected into an adapted host cell and used for protein production, using standard techniques well known in the art (see, e.g., U.S. Pat. Nos. 7,531,327; 7,537,930; 7,608,425 and 7,785,880, the Examples section of each of which is incorporated herein by reference).

The complement system is a complex cascade involving proteolytic cleavage of serum glycoproteins often activated by cell receptors. The “complement cascade” is constitutive and non-specific but it must be activated in order to function. Complement activation results in a unidirectional sequence of enzymatic and biochemical reactions. In this cascade, a specific complement protein, C5, forms two highly active, inflammatory byproducts, C5a and C5b, which jointly activate white blood cells. This in turn evokes a number of other inflammatory byproducts, including injurious cytokines, inflammatory enzymes, and cell adhesion molecules. Together, these byproducts can lead to the destruction of tissue seen in many inflammatory diseases. This cascade ultimately results in induction of the inflammatory response, phagocyte chemotaxis and opsonization, and cell lysis.

The complement system can be activated via two distinct pathways, the classical pathway and the alternate pathway. Most of the complement components are numbered (e.g., C1, C2, C3, etc.) but some are referred to as “Factors.” Some of the components must be enzymatically cleaved to activate their function; others simply combine to form complexes that are active. Active components of the classical pathway include C1q, C1r, C1s, C2a, C2b, C3a, C3b, C4a, and C4b. Active components of the alternate pathway include C3a, C3b, Factor B, Factor Ba, Factor Bb, Factor D, and Properdin. The last stage of each pathway is the same, and involves component assembly into a membrane attack complex. Active components of the membrane attack complex include C5a, C5b, C6, C7, C8, and C9n.

While any of these components of the complement system can be targeted by an antibody complex, certain of the complement components are preferred. C3a, C4a and C5a cause mast cells to release chemotactic factors such as histamine and serotonin, which attract phagocytes, antibodies and complement, etc. These form one group of preferred targets. Another group of preferred targets includes C3b, C4b and C5b, which enhance phagocytosis of foreign cells. Another preferred group of targets are the predecessor components for these two groups, i.e., C3, C4 and C5. C5b, C6, C7, C8 and C9 induce lysis of foreign cells (membrane attack complex) and form yet another preferred group of targets.

Complement C5a, like C3a, is an anaphylatoxin. It mediates inflammation and is a chemotactic attractant for induction of neutrophilic release of antimicrobial proteases and oxygen radicals. Therefore, C5a and its predecessor C5 are particularly preferred targets. By targeting C5, not only is C5a affected, but also C5b, which initiates assembly of the membrane-attack complex. Thus, C5 is another preferred target. C3b, and its predecessor C3, also are preferred targets, as both the classical and alternate complement pathways depend upon C3b. Three proteins affect the levels of this factor, C1 inhibitor, protein H and Factor I, and these are also preferred targets according to the invention. Complement regulatory proteins, such as CD46, CD55, and CD59, may be targets to which the antibody complexes bind.

Coagulation factors also are preferred targets, particularly tissue factor and thrombin. Tissue factor is also known also as tissue thromboplastin, CD142, coagulation factor III, or factor III. Tissue factor is an integral membrane receptor glycoprotein and a member of the cytokine receptor superfamily. The ligand binding extracellular domain of tissue factor consists of two structural modules with features that are consistent with the classification of tissue factor as a member of type-2 cytokine receptors. Tissue factor is involved in the blood coagulation protease cascade and initiates both the extrinsic and intrinsic blood coagulation cascades by forming high affinity complexes between the extracellular domain of tissue factor and the circulating blood coagulation factors, serine proteases factor VII or factor VIIa. These enzymatically active complexes then activate factor IX and factor X, leading to thrombin generation and clot formation.

Tissue factor is expressed by various cell types, including monocytes, macrophages and vascular endothelial cells, and is induced by IL-1, TNF-α or bacterial lipopolysaccharides. Protein kinase C is involved in cytokine activation of endothelial cell tissue factor expression. Induction of tissue factor by endotoxin and cytokines is an important mechanism for initiation of disseminated intravascular coagulation seen in patients with Gram-negative sepsis. Tissue factor also appears to be involved in a variety of non-hemostatic functions including inflammation, cancer, brain function, immune response, and tumor-associated angiogenesis. Thus, antibody complexes that target tissue factor are useful not only in the treatment of coagulopathies, but also in the treatment of sepsis, cancer, pathologic angiogenesis, and other immune and inflammatory dysregulatory diseases according to the invention. A complex interaction between the coagulation pathway and the cytokine network is suggested by the ability of several cytokines to influence tissue factor expression in a variety of cells and by the effects of ligand binding to the receptor. Ligand binding (factor VIIa) has been reported to give an intracellular calcium signal, thus indicating that tissue factor is a true receptor.

Thrombin is the activated form of coagulation factor II (prothrombin); it converts fibrinogen to fibrin. Thrombin is a potent chemotaxin for macrophages, and can alter their production of cytokines and arachidonic acid metabolites. It is of particular importance in the coagulopathies that accompany sepsis. Numerous studies have documented the activation of the coagulation system either in septic patients or following LPS administration in animal models. Despite more than thirty years of research, the mechanisms of LPS-induced liver toxicity remain poorly understood. It is now clear that they involve a complex and sequential series of interactions between cellular and humoral mediators. In the same period of time, gram-negative systemic sepsis and its sequalae have become a major health concern, attempts to use monoclonal antibodies directed against LPS or various inflammatory mediators have yielded only therapeutic failures. Antibody complexes that target both thrombin and at least one other target address the clinical failures in sepsis treatment.

In other embodiments, the antibody complexes bind to a MHC class I, MHC class II or accessory molecule, such as CD40, CD54, CD80 or CD86. The antibody complex also may bind to a T-cell activation cytokine, or to a cytokine mediator, such as NF-κB.

In certain embodiments, one of the two different targets may be a cancer cell receptor or cancer-associated antigen, particularly one that is selected from the group consisting of B-cell lineage antigens (CD19, CD20, CD21, CD22, CD23, etc.), VEGF, VEGFR, EGFR, carcinoembryonic antigen (CEA), placental growth factor (P1GF), tenascin, HER-2/neu, EGP-1, EGP-2, CD25, CD30, CD33, CD38, CD40, CD45, CD52, CD74, CD80, CD138, NCA66, CEACAM1, CEACAM6 (carcinoembryonic antigen-related cellular adhesion molecule 6), MUC1, MUC2, MUC3, MUC4, MUC16, IL-6, α-fetoprotein (AFP), A3, CA125, colon-specific antigen-p (CSAp), folate receptor, HLA-DR, human chorionic gonadotropin (HCG), Ia, EL-2, insulin-like growth factor (IGF) and IGF receptor, KS-1, Le(y), MAGE, necrosis antigens, PAM-4, prostatic acid phosphatase (PAP), Pr1, prostate specific antigen (PSA), prostate specific membrane antigen (PSMA), S100, T101, TAC, TAG72, TRAIL receptors, and carbonic anhydrase IX.

Targets associated with sepsis and immune dysregulation and other immune disorders include MIF, IL-1, IL-6, IL-8, CD74, CD83, and C5aR. Antibodies and inhibitors against C5aR have been found to improve survival in rodents with sepsis (Huber-Lang et al., FASEB J 2002; 16:1567-1574; Riedemann et al., J Clin Invest 2002; 110:101-108) and septic shock and adult respiratory distress syndrome in monkeys (Hangen et al., J Surg Res 1989; 46:195-199; Stevens et al., J Clin Invest 1986; 77:1812-1816). Thus, for sepsis, one of the two different targets preferably is a target that is associated with infection, such as LPS/C5a. Other preferred targets include HMGB-1, tissue factor, CD14, VEGF, and IL-6, each of which is associated with septicemia or septic shock. Preferred antibody complexes are those that target two or more targets from HMGB-1, tissue factor and MIF, such as MIF/tissue factor, and HMGB-1/tissue factor.

In still other embodiments, one of the different targets may be a target that is associated with graft versus host disease or transplant rejection, such as MIF (Lo et al., Bone Marrow Transplant, 30(6):375-80 (2002)). One of the different targets also may be one that associated with acute respiratory distress syndrome, such as IL-8 (Bouros et al., PMC Pulm Med, 4(1):6 (2004), atherosclerosis or restenosis, such as MIF (Chen et al., Arterioscler Thromb Vasc Biol, 24(4):709-14 (2004), asthma, such as IL-18 (Hata et al., Int Immunol, Oct. 11, 2004 Epub ahead of print), a granulomatous disease, such as TNF-α (Ulbricht et al., Arthritis Rheum, 50(8):2717-8 (2004), a neuropathy, such as carbamylated EPO (erythropoietin) (Leist et al., Science 305(5681):164-5 (2004), or cachexia, such as IL-6 and TNF-α.

Other targets include C5a, LPS, IFN-gamma, B7; CD2, CD4, CD14, CD18, CD11a, CD11b, CD11c, CD14, CD18, CD27, CD29, CD38, CD40L, CD52, CD64, CD83, CD147, CD154. Activation of mononuclear cells by certain microbial antigens, including LPS, can be inhibited to some extent by antibodies to CD18, CD11b, or CD11c, which thus implicate β₂-integrins (Cuzzola et al., J Immunol 2000; 164:5871-5876; Medvedev et al., J Immunol 1998; 160: 4535-4542). CD83 has been found to play a role in giant cell arteritis (GCA), which is a systemic vasculitis that affects medium- and large-size arteries, predominately the extracranial branches of the aortic arch and of the aorta itself, resulting in vascular stenosis and subsequent tissue ischemia, and the severe complications of blindness, stroke and aortic arch syndrome (Weyand and Goronzy, N Engl J Med 2003; 349:160-169; Hunder and Valente, In: INFLAMMATORY DISEASES OF BLOOD VESSELS. G. S. Hoffman and C. M. Weyand, eds, Marcel Dekker, New York, 2002; 255-265). Antibodies to CD83 were found to abrogate vasculitis in a SCID mouse model of human GCA (Ma-Krupa et al., J Exp Med 2004; 199:173-183), suggesting to these investigators that dendritic cells, which express CD83 when activated, are critical antigen-processing cells in GCA. In these studies, they used a mouse anti-CD83 MAb (IgG1 clone HB15e from Research Diagnostics). CD154, a member of the TNF family, is expressed on the surface of CD4-positive T-lymphocytes, and it has been reported that a humanized monoclonal antibody to CD154 produced significant clinical benefit in patients with active systemic lupus erythematosus (SLE) (Grammar et al., J Clin Invest 2003; 112:1506-1520). It also suggests that this antibody might be useful in other autoimmune diseases (Kelsoe, J Clin Invest 2003; 112:1480-1482). Indeed, this antibody was also reported as effective in patients with refractory immune thrombocytopenic purpura (Kuwana et al., Blood 2004; 103:1229-1236).

In rheumatoid arthritis, a recombinant interleukin-1 receptor antagonist, IL-1Ra or anakinra, has shown activity (Cohen et al., Ann Rheum Dis 2004; 63:1062-8; Cohen, Rheum Dis Clin North Am 2004; 30:365-80). An improvement in treatment of these patients, which hitherto required concomitant treatment with methotrexate, is to combine anakinra with one or more of the anti-proinflammatory effector cytokines or anti-proinflammatory effector chemokines (as listed above). Indeed, in a review of antibody therapy for rheumatoid arthritis, Taylor (Curr Opin Pharmacol 2003; 3:323-328) suggests that in addition to TNF, other antibodies to such cytokines as IL-1, IL-6, IL-8, IL-15, IL-17 and IL-18, are useful.

The pharmaceutical composition of the present invention may be used to treat a subject having a metabolic disease, such amyloidosis, or a neurodegenerative disease, such as Alzheimer's disease. Bapineuzumab is in clinical trials for Alzheimer's disease therapy. Other antibodies proposed for therapy of Alzheimer's disease include Alz 50 (Ksiezak-Reding et al., 1987, J Biol Chem 263:7943-47), gantenerumab, and solanezumab. Infliximab, an anti-TNF-α antibody, has been reported to reduce amyloid plaques and improve cognition.

In a preferred embodiment, diseases that may be treated using the claimed compositions and methods include cardiovascular diseases, such as fibrin clots, atherosclerosis, myocardial ischemia and infarction. Antibodies to fibrin (e.g., scFv(59D8); T2G1s; MH1) are known and in clinical trials as imaging agents for disclosing said clots and pulmonary emboli, while anti-granulocyte antibodies, such as MN-3, MN-15, anti-NCA95, and anti-CD15 antibodies, can target myocardial infarcts and myocardial ischemia. (See, e.g., U.S. Pat. Nos. 5,487,892; 5,632,968; 6,294,173; 7,541,440, the Examples section of each incorporated herein by reference) Anti-macrophage, anti-low-density lipoprotein (LDL), anti-MIF, and anti-CD74 (e.g., hLL1) antibodies can be used to target atherosclerotic plaques. Abciximab (anti-glycoprotein IIb/IIIa) has been approved for adjuvant use for prevention of restenosis in percutaneous coronary interventions and the treatment of unstable angina (Waldmann et al., 2000, Hematol 1:394-408). Antibodies against oxidized LDL induced a regression of established atherosclerosis in a mouse model (Ginsberg, 2007, J Am Coll Cardiol 52:2319-21). Anti-ICAM-1 antibody was shown to reduce ischemic cell damage after cerebral artery occlusion in rats (Zhang et al., 1994, Neurology 44:1747-51). Commercially available monoclonal antibodies to leukocyte antigens are represented by: OKT anti-T-cell monoclonal antibodies (available from Ortho Pharmaceutical Company) which bind to normal T-lymphocytes; the monoclonal antibodies produced by the hybridomas having the ATCC accession numbers HB44, HB55, HB12, HB78 and HB2; G7E11, W8E7, NKP15 and G022 (Becton Dickinson); NEN9.4 (New England Nuclear); and FMC11 (Sera Labs). A description of antibodies against fibrin and platelet antigens is contained in Knight, Semin. Nucl. Med., 20:52-67 (1990).

Other antibodies that may be used include antibodies against infectious disease agents, such as bacteria, viruses, mycoplasms or other pathogens. Many antibodies against such infectious agents are known in the art and any such known antibody may be used in the claimed methods and compositions. For example, antibodies against the gp120 glycoprotein antigen of human immunodeficiency virus I (HIV-1) are known, and certain of such antibodies can have an immunoprotective role in humans. See, e.g., Rossi et al., Proc. Natl. Acad. Sci. USA. 86:8055-8058, 1990. Known anti-HIV antibodies include the anti-envelope antibody described by Johansson et al. (AIDS, 2006 Oct. 3; 20(15):1911-5), as well as the anti-HIV antibodies described and sold by Polymun (Vienna, Austria), also described in U.S. Pat. No. 5,831,034, U.S. Pat. No. 5,911,989, and Vcelar et al., AIDS 2007; 21(16):2161-2170 and Joos et al., Antimicrob. Agents Chemother. 2006; 50(5):1773-9, all incorporated herein by reference.

Antibodies against malaria parasites can be directed against the sporozoite, merozoite, schizont and gametocyte stages. Monoclonal antibodies have been generated against sporozoites (cirumsporozoite antigen), and have been shown to neutralize sporozoites in vitro and in rodents (N. Yoshida et al., Science 207:71-73, 1980). Several groups have developed antibodies to T. gondii, the protozoan parasite involved in toxoplasmosis (Kasper et al., J. Immunol. 129:1694-1699, 1982; Id., 30:2407-2412, 1983). Antibodies have been developed against schistosomular surface antigens and have been found to act against schistosomulae in vivo or in vitro (Simpson et al., Parasitology, 83:163-177, 1981; Smith et al., Parasitology, 84:83-91, 1982: Gryzch et al., J. Immunol., 129:2739-2743, 1982; Zodda et al., J. Immunol. 129:2326-2328, 1982; Dissous et al., J. Immunol., 129:2232-2234, 1982)

Trypanosoma cruzi is the causative agent of Chagas' disease, and is transmitted by blood-sucking reduviid insects. An antibody has been generated that specifically inhibits the differentiation of one form of the parasite to another (epimastigote to trypomastigote stage) in vitro, and which reacts with a cell-surface glycoprotein; however, this antigen is absent from the mammalian (bloodstream) forms of the parasite (Sher et al., Nature, 300:639-640, 1982).

Anti-fungal antibodies are known in the art, such as anti-Sclerotinia antibody (U.S. Pat. No. 7,910,702); antiglucuronoxylomannan antibody (Zhong and Priofski, 1998, Clin Diag Lab Immunol 5:58-64); anti-Candida antibodies (Matthews and Burnie, 2001, Curr Opin Investig Drugs 2:472-76); and anti-glycosphingolipid antibodies (Toledo et al., 2010, BMC Microbiol 10:47).

Suitable antibodies have been developed against most of the microorganism (bacteria, viruses, protozoa, fungi, other parasites) responsible for the majority of infections in humans, and many have been used previously for in vitro diagnostic purposes. These antibodies, and newer antibodies that can be generated by conventional methods, are appropriate for use in the present invention.

Immunoconjugates

In certain embodiments, the antibodies or fragments thereof may be conjugated to one or more therapeutic or diagnostic agents. The therapeutic agents do not need to be the same but can be different, e.g. a drug and a radioisotope. For example, ¹³¹I can be incorporated into a tyrosine of an antibody or fusion protein and a drug attached to an epsilon amino group of a lysine residue. Therapeutic and diagnostic agents also can be attached, for example to reduced SH groups and/or to carbohydrate side chains. Many methods for making covalent or non-covalent conjugates of therapeutic or diagnostic agents with antibodies or fusion proteins are known in the art and any such known method may be utilized.

A therapeutic or diagnostic agent can be attached at the hinge region of a reduced antibody component via disulfide bond formation. Alternatively, such agents can be attached using a heterobifunctional cross-linker, such as N-succinyl 3-(2-pyridyldithio)propionate (SPDP). Yu et al., Int. J. Cancer 56: 244 (1994). General techniques for such conjugation are well-known in the art. See, for example, Wong, CHEMISTRY OF PROTEIN CONJUGATION AND CROSS-LINKING (CRC Press 1991); Upeslacis et al., “Modification of Antibodies by Chemical Methods,” in MONOCLONAL ANTIBODIES: PRINCIPLES AND APPLICATIONS, Birch et al. (eds.), pages 187-230 (Wiley-Liss, Inc. 1995); Price, “Production and Characterization of Synthetic Peptide-Derived Antibodies,” in MONOCLONAL ANTIBODIES: PRODUCTION, ENGINEERING AND CLINICAL APPLICATION, Ritter et al. (eds.), pages 60-84 (Cambridge University Press 1995). Alternatively, the therapeutic or diagnostic agent can be conjugated via a carbohydrate moiety in the Fc region of the antibody. The carbohydrate group can be used to increase the loading of the same agent that is bound to a thiol group, or the carbohydrate moiety can be used to bind a different therapeutic or diagnostic agent.

Methods for conjugating peptides to antibody components via an antibody carbohydrate moiety are well-known to those of skill in the art. See, for example, Shih et al., Int. J. Cancer 41: 832 (1988); Shih et al., Int. J. Cancer 46: 1101 (1990); and Shih et al., U.S. Pat. No. 5,057,313, incorporated herein in their entirety by reference. The general method involves reacting an antibody component having an oxidized carbohydrate portion with a carrier polymer that has at least one free amine function. This reaction results in an initial Schiff base (imine) linkage, which can be stabilized by reduction to a secondary amine to form the final conjugate.

The Fc region may be absent if the antibody used as the antibody component of the immunoconjugate is an antibody fragment. However, it is possible to introduce a carbohydrate moiety into the light chain variable region of a full length antibody or antibody fragment. See, for example, Leung et al., J. Immunol. 154: 5919 (1995); Hansen et al., U.S. Pat. No. 5,443,953 (1995), Leung et al., U.S. Pat. No. 6,254,868, incorporated herein by reference in their entirety. The engineered carbohydrate moiety is used to attach the therapeutic or diagnostic agent.

In some embodiments, a chelating agent may be attached to an antibody, antibody fragment or fusion protein and used to chelate a therapeutic or diagnostic agent, such as a radionuclide. Exemplary chelators include but are not limited to DTPA (such as Mx-DTPA), DOTA, TETA, NETA or NOTA. Methods of conjugation and use of chelating agents to attach metals or other ligands to proteins are well known in the art (see, e.g., U.S. Pat. No. 7,563,433, the Examples section of which is incorporated herein by reference).

In certain embodiments, radioactive metals or paramagnetic ions may be attached to proteins or peptides by reaction with a reagent having a long tail, to which may be attached a multiplicity of chelating groups for binding ions. Such a tail can be a polymer such as a polylysine, polysaccharide, or other derivatized or derivatizable chains having pendant groups to which can be bound chelating groups such as, e.g., ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), porphyrins, polyamines, crown ethers, bis-thiosemicarbazones, polyoximes, and like groups known to be useful for this purpose.

Chelates may be directly linked to antibodies or peptides, for example as disclosed in U.S. Pat. No. 4,824,659, incorporated herein in its entirety by reference. Particularly useful metal-chelate combinations include 2-benzyl-DTPA and its monomethyl and cyclohexyl analogs, used with diagnostic isotopes in the general energy range of 60 to 4,000 keV, such as ¹²⁵I, ¹³¹I, ¹²³I, ¹²⁴I, ⁶²Cu, ⁶⁴Cu, ¹⁸F, ¹¹¹In, ⁶⁷Ga, ⁶⁸Ga, ^(99m)Tc, ^(94m)Tc, ¹¹C, ¹³N, ¹⁵O, ⁷⁶Br, for radioimaging. The same chelates, when complexed with non-radioactive metals, such as manganese, iron and gadolinium are useful for MM. Macrocyclic chelates such as NOTA, DOTA, and TETA are of use with a variety of metals and radiometals, most particularly with radionuclides of gallium, yttrium and copper, respectively. Such metal-chelate complexes can be made very stable by tailoring the ring size to the metal of interest. Other ring-type chelates such as macrocyclic polyethers, which are of interest for stably binding nuclides, such as ²²³Ra for RAIT are encompassed.

More recently, methods of ¹⁸F-labeling of use in PET scanning techniques have been disclosed, for example by reaction of F-18 with a metal or other atom, such as aluminum. The ¹⁸F—Al conjugate may be complexed with chelating groups, such as DOTA, NOTA or NETA that are attached directly to antibodies or used to label targetable constructs in pre-targeting methods. Such F-18 labeling techniques are disclosed in U.S. Pat. No. 7,563,433, the Examples section of which is incorporated herein by reference.

DOCK-AND-LOCK™ (DNL™)

In preferred embodiments, a bispecific antibody, either alone or else complexed to one or more effectors such as cytokines, is formed as a DOCK-AND-LOCK™ (DNL™) complex (see, e.g., U.S. Pat. Nos. 7,521,056; 7,527,787; 7,534,866; 7,550,143; 7,666,400; 7,901,680; 7,906,118; 7,981,398; 8,003,111, the Examples section of each of which is incorporated herein by reference.) Generally, the technique takes advantage of the specific and high-affinity binding interactions that occur between a dimerization and docking domain (DDD) sequence of the regulatory (R) subunits of cAMP-dependent protein kinase (PKA) and an anchor domain (AD) sequence derived from any of a variety of AKAP proteins (Baillie et al., FEBS Letters. 2005; 579: 3264. Wong and Scott, Nat. Rev. Mol. Cell Biol. 2004; 5: 959). The DDD and AD peptides may be attached to any protein, peptide or other molecule. Because the DDD sequences spontaneously dimerize and bind to the AD sequence, the technique allows the formation of complexes between any selected molecules that may be attached to DDD or AD sequences.

Although the standard DNL™ complex comprises a trimer with two DDD-linked molecules attached to one AD-linked molecule, variations in complex structure allow the formation of dimers, trimers, tetramers, pentamers, hexamers and other multimers. In some embodiments, the DNL™ complex may comprise two or more antibodies, antibody fragments or fusion proteins which bind to the same antigenic determinant or to two or more different antigens. The DNL™ complex may also comprise one or more other effectors, such as proteins, peptides, immunomodulators, cytokines, interleukins, interferons, binding proteins, peptide ligands, carrier proteins, toxins, ribonucleases such as onconase, inhibitory oligonucleotides such as siRNA, antigens or xenoantigens, polymers such as PEG, enzymes, therapeutic agents, hormones, cytotoxic agents, anti-angiogenic agents, pro-apoptotic agents or any other molecule or aggregate.

PKA, which plays a central role in one of the best studied signal transduction pathways triggered by the binding of the second messenger cAMP to the R subunits, was first isolated from rabbit skeletal muscle in 1968 (Walsh et al., J. Biol. Chem. 1968; 243:3763). The structure of the holoenzyme consists of two catalytic subunits held in an inactive form by the R subunits (Taylor, J. Biol. Chem. 1989; 264:8443). Isozymes of PKA are found with two types of R subunits (RI and MI), and each type has α and β isoforms (Scott, Pharmacol. Ther. 1991; 50:123). Thus, the four isoforms of PKA regulatory subunits are RIα, R1β, RIIα and R1113, each of which comprises a DDD moiety amino acid sequence. The R subunits have been isolated only as stable dimers and the dimerization domain has been shown to consist of the first 44 amino-terminal residues of RIIα (Newlon et al., Nat. Struct. Biol. 1999; 6:222). As discussed below, similar portions of the amino acid sequences of other regulatory subunits are involved in dimerization and docking, each located near the N-terminal end of the regulatory subunit. Binding of cAMP to the R subunits leads to the release of active catalytic subunits for a broad spectrum of serine/threonine kinase activities, which are oriented toward selected substrates through the compartmentalization of PKA via its docking with AKAPs (Scott et al., J. Biol. Chem. 1990; 265; 21561)

Since the first AKAP, microtubule-associated protein-2, was characterized in 1984 (Lohmann et al., Proc. Natl. Acad. Sci USA 1984; 81:6723), more than 50 AKAPs that localize to various sub-cellular sites, including plasma membrane, actin cytoskeleton, nucleus, mitochondria, and endoplasmic reticulum, have been identified with diverse structures in species ranging from yeast to humans (Wong and Scott, Nat. Rev. Mol. Cell Biol. 2004; 5:959). The AD of AKAPs for PKA is an amphipathic helix of 14-18 residues (Carr et al., J. Biol. Chem. 1991; 266:14188). The amino acid sequences of the AD are varied among individual AKAPs, with the binding affinities reported for RII dimers ranging from 2 to 90 nM (Alto et al., Proc. Natl. Acad. Sci. USA 2003; 100:4445). AKAPs will only bind to dimeric R subunits. For human RIIα, the AD binds to a hydrophobic surface formed by the 23 amino-terminal residues (Colledge and Scott, Trends Cell Biol. 1999; 6:216). Thus, the dimerization domain and AKAP binding domain of human RIIα are both located within the same N-terminal 44 amino acid sequence (Newlon et al., Nat. Struct. Biol. 1999; 6:222; Newlon et al., EMBO J. 2001; 20:1651), which is termed the DDD herein.

We have developed a platform technology to utilize the DDD of human PKA regulatory subunits and the AD of AKAP as an excellent pair of linker modules for docking any two entities, referred to hereafter as A and B, into a noncovalent complex, which could be further locked into a DNL™ complex through the introduction of cysteine residues into both the DDD and AD at strategic positions to facilitate the formation of disulfide bonds. The general methodology of the approach is as follows. Entity A is constructed by linking a DDD sequence to a precursor of A, resulting in a first component hereafter referred to as a. Because the DDD sequence would effect the spontaneous formation of a dimer, A would thus be composed of a₂. Entity B is constructed by linking an AD sequence to a precursor of B, resulting in a second component hereafter referred to as b. The dimeric motif of DDD contained in a₂ will create a docking site for binding to the AD sequence contained in b, thus facilitating a ready association of a₂ and b to form a binary, trimeric complex composed of a₂b. This binding event is stabilized with a subsequent reaction to covalently secure the two entities via disulfide bridges, which occurs very efficiently based on the principle of effective local concentration because the initial binding interactions should bring the reactive thiol groups placed onto both the DDD and AD into proximity (Chmura et al., Proc. Natl. Acad. Sci. USA 2001; 98:8480) to ligate site-specifically. Using various combinations of linkers, adaptor modules and precursors, a wide variety of DNL™ constructs of different stoichiometry may be produced and used (see, e.g., U.S. Pat. Nos. 7,550,143; 7,521,056; 7,534,866; 7,527,787 and 7,666,400.)

By attaching the DDD and AD away from the functional groups of the two precursors, such site-specific ligations are also expected to preserve the original activities of the two precursors. This approach is modular in nature and potentially can be applied to link, site-specifically and covalently, a wide range of substances, including peptides, proteins, antibodies, antibody fragments, and other effector moieties with a wide range of activities. Utilizing the fusion protein method of constructing AD and DDD conjugated effectors described in the Examples below, virtually any protein or peptide may be incorporated into a DNL™ construct. However, the technique is not limiting and other methods of conjugation may be utilized.

A variety of methods are known for making fusion proteins, including nucleic acid synthesis, hybridization and/or amplification to produce a synthetic double-stranded nucleic acid encoding a fusion protein of interest. Such double-stranded nucleic acids may be inserted into expression vectors for fusion protein production by standard molecular biology techniques (see, e.g. Sambrook et al., MOLECULAR CLONING, A LABORATORY MANUAL, 2^(nd) Ed, 1989). In such preferred embodiments, the AD and/or DDD moiety may be attached to either the N-terminal or C-terminal end of an effector protein or peptide. However, the skilled artisan will realize that the site of attachment of an AD or DDD moiety to an effector moiety may vary, depending on the chemical nature of the effector moiety and the part(s) of the effector moiety involved in its physiological activity. Site-specific attachment of a variety of effector moieties may be performed using techniques known in the art, such as the use of bivalent cross-linking reagents and/or other chemical conjugation techniques.

Dock-and-Lock™ (DNL™) technology has been used to produce a variety of complexes in assorted formats (Rossi et al., 2012, Bioconjug Chem 23:309-23). Bispecific hexavalent antibodies (bsHexAbs) based on veltuzumab (anti-CD20) and epratuzumab (anti-CD22) were constructed by combining a stabilized (Fab)₂ fused to a dimerization and docking domain (DDD) with an IgG containing an anchor domain (AD) appended at the C-terminus of each heavy chain (C_(H)3-AD2-IgG) (Rossi et al., 2009, Blood 113, 6161-71). Compared to mixtures of their parental mAbs, these Fc-based bsHexAbs, referred to henceforth as “Fc-bsHexAbs”, induced unique signaling events (Gupta et al., 2010, Blood 116:3258-67), and exhibited potent cytotoxicity in vitro. However, the Fc-bsHexAbs were cleared from circulation of mice approximately twice as fast as the parental mAbs (Rossi et al., 2009, Blood 113, 6161-71). Although the Fc-bsHexAbs are highly stable ex vivo, it is possible that some dissociation occurs in vivo, for example by intracellular processing. Further, the Fc-bsHexAbs lack CDC activity.

Fc-based immunocytokines have also been assembled as DNL™ complexes, comprising two or four molecules of interferon-alpha 2b (IFNα2b) fused to the C-terminal end of the C_(H)3-AD2-IgG Fc (Rossi et al., 2009, Blood 114:3864-71; Rossi et al., 2010, Cancer Res 70:7600-09; Rossi et al., 2011, Blood 118:1877-84). The Fc-IgG-IFNα maintained high specific activity, approaching that of recombinant IFNα, and were remarkably potent in vitro and in vivo against non-Hodgkin lymphoma (NHL) xenografts. The T₁₁₂ of the Fc-IgG-IFNα in mice was longer than PEGylated IFNα, but half as long as the parental mAbs. Similar to the Fc-bsHexAbs, the Fc-IgG-IFNα dissociated in vivo over time and exhibited diminished CDC, but ADCC was enhanced.

Structure-Function Relationships in AD and DDD Moieties

For different types of DNL™ constructs, different AD or DDD sequences may be utilized. Exemplary DDD and AD sequences are provided below.

DDD1 (SEQ ID NO: 1) SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA DDD2 (SEQ ID NO: 2) CGHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA AD1 (SEQ ID NO: 3) QIEYLAKQIVDNAIQQA AD2 (SEQ ID NO: 4) CGQIEYLAKQIVDNAIQQAGC

The skilled artisan will realize that DDD1 and DDD2 are based on the DDD sequence of the human RIIα isoform of protein kinase A. However, in alternative embodiments, the DDD and AD moieties may be based on the DDD sequence of the human RIα form of protein kinase A and a corresponding AKAP sequence, as exemplified in DDD3, DDD3C and AD3 below.

DDD3 (SEQ ID NO: 5) SLRECELYVQKHNIQALLKDSIVQLCTARPERPMAFLREYFERLEKEEAK DDD3C (SEQ ID NO: 6) MSCGGSLRECELYVQKHNIQALLKDSIVQLCTARPERPMAFLREYFERLE KEEAK AD3 (SEQ ID NO: 7) CGFEELAWKIAKMIWSDVFQQGC

In other alternative embodiments, other sequence variants of AD and/or DDD moieties may be utilized in construction of the DNL™ complexes. For example, there are only four variants of human PKA DDD sequences, corresponding to the DDD moieties of PKA RIα, RIIα, RIβ and RIIβ. The RIIα DDD sequence is the basis of DDD1 and DDD2 disclosed above. The four human PKA DDD sequences are shown below. The DDD sequence represents residues 1-44 of Mx, 1-44 of RIIβ, 12-61 of RIα and 13-66 of RIβ. (Note that the sequence of DDD1 is modified slightly from the human PKA RIIα DDD moiety.)

PKA RIα (SEQ ID NO: 8) SLRECELYVQKHNIQALLKDVSIVQLCTARPERPMAFLREYFEKLEKEE AK PKA RIβ (SEQ ID NO: 9) SLKGCELYVQLHGIQQVLKDCIVHLCISKPERPMKFLREHFEKLEKEEN RQILA PKA RIIα (SEQ ID NO: 10) SHIQIPPGLTELLQGYTVEVGQQPPDLVDFAVEYFTRLREARRQ PKA RIIβ (SEQ ID NO: 11) SIEIPAGLTELLQGFTVEVLRHQPADLLEFALQHFTRLQQENER

The structure-function relationships of the AD and DDD domains have been the subject of investigation. (See, e.g., Burns-Hamuro et al., 2005, Protein Sci 14:2982-92; Carr et al., 2001, J Biol Chem 276:17332-38; Alto et al., 2003, Proc Natl Acad Sci USA 100:4445-50; Hundsrucker et al., 2006, Biochem J 396:297-306; Stokka et al., 2006, Biochem J400:493-99; Gold et al., 2006, Mol Cell 24:383-95; Kinderman et al., 2006, Mol Cell 24:397-408, the entire text of each of which is incorporated herein by reference.)

For example, Kinderman et al. (2006, Mol Cell 24:397-408) examined the crystal structure of the AD-DDD binding interaction and concluded that the human DDD sequence contained a number of conserved amino acid residues that were important in either dimer formation or AKAP binding, underlined in SEQ ID NO:1 below. (See FIG. 1 of Kinderman et al., 2006, incorporated herein by reference.) The skilled artisan will realize that in designing sequence variants of the DDD sequence, one would desirably avoid changing any of the underlined residues, while conservative amino acid substitutions might be made for residues that are less critical for dimerization and AKAP binding.

(SEQ ID NO: 1) SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA

As discussed in more detail below, conservative amino acid substitutions have been characterized for each of the twenty common L-amino acids. Thus, based on the data of Kinderman (2006) and conservative amino acid substitutions, potential alternative DDD sequences based on SEQ ID NO:1 are shown in Table 2. In devising Table 2, only highly conservative amino acid substitutions were considered. For example, charged residues were only substituted for residues of the same charge, residues with small side chains were substituted with residues of similar size, hydroxyl side chains were only substituted with other hydroxyls, etc. Because of the unique effect of proline on amino acid secondary structure, no other residues were substituted for proline. A limited number of such potential alternative DDD moiety sequences are shown in SEQ ID NO:12 to SEQ ID NO:31 below. The skilled artisan will realize that an almost unlimited number of alternative species within the genus of DDD moieties can be constructed by standard techniques, for example using a commercial peptide synthesizer or well known site-directed mutagenesis techniques. The effect of the amino acid substitutions on AD moiety binding may also be readily determined by standard binding assays, for example as disclosed in Alto et al. (2003, Proc Natl Acad Sci USA 100:4445-50).

TABLE 2 Conservative Amino Acid Substitutions in DDD1 (SEQ ID NO: 1). Consensus sequence disclosed as SEQ ID NO: 87. S H I Q I P P G L T E L L Q G Y T V E V L R T K N A S D N A S D K R Q Q P P D L V E F A V E Y F T R L R E A R A N N E D L D S K K D L K L I I I V V V THIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 12) SKIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 13) SRIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 14) SHINIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 15) SHIQIPPALTELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 16) SHIQIPPGLSELLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 17) SHIQIPPGLTDLLQGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO :18) SHIQIPPGLTELLNGYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 19) SHIQIPPGLTELLQAYTVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 20) SHIQIPPGLTELLQGYSVEVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 21) SHIQIPPGLTELLQGYTVDVLRQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 22) SHIQIPPGLTELLQGYTVEVLKQQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 23) SHIQIPPGLTELLQGYTVEVLRNQPPDLVEFAVEYFTRLREARA (SEQ ID NO: 24) SHIQIPPGLTELLQGYTVEVLRQNPPDLVEFAVEYFTRLREARA (SEQ ID NO: 25) SHIQIPPGLTELLQGYTVEVLRQQPPELVEFAVEYFTRLREARA (SEQ ID NO: 26) SHIQIPPGLTELLQGYTVEVLRQQPPDLVDFAVEYFTRLREARA (SEQ ID NO: 27) SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFLVEYFTRLREARA (SEQ ID NO: 28) SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFIVEYFTRLREARA (SEQ ID NO: 29) SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFVVEYFTRLREARA (SEQ ID NO: 30) SHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVDYFTRLREARA (SEQ ID NO: 31)

Alto et al. (2003, Proc Natl Acad Sci USA 100:4445-50) performed a bioinformatic analysis of the AD sequence of various AKAP proteins to design an RII selective AD sequence called AKAP-IS (SEQ ID NO:3), with a binding constant for DDD of 0.4 nM. The AKAP-IS sequence was designed as a peptide antagonist of AKAP binding to PKA. Residues in the AKAP-IS sequence where substitutions tended to decrease binding to DDD are underlined in SEQ ID NO:3 below. The skilled artisan will realize that in designing sequence variants of the AD sequence, one would desirably avoid changing any of the underlined residues, while conservative amino acid substitutions might be made for residues that are less critical for DDD binding. Table 3 shows potential conservative amino acid substitutions in the sequence of AKAP-IS (AD1, SEQ ID NO:3), similar to that shown for DDD1 (SEQ ID NO:1) in Table 2 above.

A limited number of such potential alternative AD moiety sequences are shown in SEQ ID NO:32 to SEQ ID NO:49 below. Again, a very large number of species within the genus of possible AD moiety sequences could be made, tested and used by the skilled artisan, based on the data of Alto et al. (2003). It is noted that FIG. 2 of Alto (2003) shows an even large number of potential amino acid substitutions that may be made, while retaining binding activity to DDD moieties, based on actual binding experiments.

AKAP-IS (SEQ ID NO: 3) QIEYLAKQIVDNAIQQA

TABLE 3 Conservative Amino Acid Substitutions in AD1 (SEQ ID NO: 3). Consensus sequence disclosed as SEQ ID NO: 88. Q I E Y L A K Q I V D N A I Q Q A N L D F I R N E Q N N L V T V I S V NIEYLAKQIVDNAIQQA (SEQ ID NO: 32) QLEYLAKQIVDNAIQQA (SEQ ID NO: 33) QVEYLAKQIVDNAIQQA (SEQ ID NO: 34) QIDYLAKQIVDNAIQQA (SEQ ID NO: 35) QIEFLAKQIVDNAIQQA (SEQ ID NO: 36) QIETLAKQIVDNAIQQA (SEQ ID NO: 37) QIESLAKQIVDNAIQQA (SEQ ID NO: 38) QIEYIAKQIVDNAIQQA (SEQ ID NO: 39) QIEYVAKQIVDNAIQQA (SEQ ID NO: 40) QIEYLARQIVDNAIQQA (SEQ ID NO: 41) QIEYLAKNIVDNAIQQA (SEQ ID NO: 42) QIEYLAKQIVENAIQQA (SEQ ID NO: 43) QIEYLAKQIVDQAIQQA (SEQ ID NO: 44) QIEYLAKQIVDNAINQA (SEQ ID NO: 45) QIEYLAKQIVDNAIQNA (SEQ ID NO: 46) QIEYLAKQIVDNAIQQL (SEQ ID NO: 47) QIEYLAKQIVDNAIQQI (SEQ ID NO: 48) QIEYLAKQIVDNAIQQV (SEQ ID NO: 49)

Gold et al. (2006, Mol Cell 24:383-95) utilized crystallography and peptide screening to develop a SuperAKAP-IS sequence (SEQ ID NO:50), exhibiting a five order of magnitude higher selectivity for the RII isoform of PKA compared with the RI isoform. Underlined residues indicate the positions of amino acid substitutions, relative to the AKAP-IS sequence, which increased binding to the DDD moiety of RIIα. In this sequence, the N-terminal Q residue is numbered as residue number 4 and the C-terminal A residue is residue number 20. Residues where substitutions could be made to affect the affinity for RIIα were residues 8, 11, 15, 16, 18, 19 and 20 (Gold et al., 2006). It is contemplated that in certain alternative embodiments, the SuperAKAP-IS sequence may be substituted for the AKAP-IS AD moiety sequence to prepare DNL™ constructs. Other alternative sequences that might be substituted for the AKAP-IS AD sequence are shown in SEQ ID NO:51-53. Substitutions relative to the AKAP-IS sequence are underlined. It is anticipated that, as with the AD2 sequence shown in SEQ ID NO:4, the AD moiety may also include the additional N-terminal residues cysteine and glycine and C-terminal residues glycine and cysteine.

SuperAKAP-IS (SEQ ID NO: 50) QIEYVAKQIVDYAIHQA Alternative AKAP sequences (SEQ ID NO: 51) QIEYKAKQIVDHAIHQA (SEQ ID NO: 52) QIEYHAKQIVDHAIHQA (SEQ ID NO: 53) QIEYVAKQIVDHAIHQA

FIG. 2 of Gold et al. disclosed additional DDD-binding sequences from a variety of AKAP proteins, shown below.

Ru-Specific AKAPs AKAP-KL (SEQ ID NO: 54) PLEYQAGLLVQNAIQQAI AKAP79 (SEQ ID NO: 55) LLIETASSLVKNAIQLSI AKAP-Lbc (SEQ ID NO: 56) LIEEAASRIVDAVIEQVK RI-Specific AKAPs AKAPce (SEQ ID NO: 57) ALYQFADRFSELVISEAL RIAD (SEQ ID NO: 58) LEQVANQLADQIIKEAT PV38 (SEQ ID NO: 59) FEELAWKIAKMIWSDVF Dual-Specificity AKAPs AKAP7 (SEQ ID NO: 60) ELVRLSKRLVENAVLKAV MAP2D (SEQ ID NO: 61) TAEEVSARIVQVVTAEAV DAKAP1 (SEQ ID NO: 62) QIKQAAFQLISQVILEAT DAKAP2 (SEQ ID NO: 63) LAWKIAKMIVSDVMQQ

Stokka et al. (2006, Biochem J400:493-99) also developed peptide competitors of AKAP binding to PKA, shown in SEQ ID NO:64-66. The peptide antagonists were designated as Ht31 (SEQ ID NO:64), RIAD (SEQ ID NO:65) and PV-38 (SEQ ID NO:66). The Ht-31 peptide exhibited a greater affinity for the RII isoform of PKA, while the RIAD and PV-38 showed higher affinity for RI.

Ht31 (SEQ ID NO: 64) DLIEEAASRIVDAVIEQVKAAGAY RIAD (SEQ ID NO: 65) LEQYANQLADQIIKEATE PV-38 (SEQ ID NO: 66) FEELAWKIAKMIWSDVFQQC

Hundsrucker et al. (2006, Biochem J 396:297-306) developed still other peptide competitors for AKAP binding to PKA, with a binding constant as low as 0.4 nM to the DDD of the RII form of PKA. The sequences of various AKAP antagonistic peptides are provided in Table 1 of Hundsrucker et al., reproduced in Table 4 below. AKAPIS represents a synthetic RII subunit-binding peptide. All other peptides are derived from the RII-binding domains of the indicated AKAPs.

TABLE 4 AKAP Peptide sequences Peptide Sequence AKAPIS QIEYLAKQIVDNAIQQA (SEQ ID NO: 3) AKAPIS-P QIEYLAKQIPDNAIQQA (SEQ ID NO: 67) Ht31 KGADLIEEAASRIVDAVIEQVKAAG (SEQ ID NO: 68) Ht31-P KGADLIEEAASRIPDAPIEQVKAAG (SEQ ID NO: 69) AKAP7δ-wt-pep PEDAELVRLSKRLVENAVLKAVQQY (SEQ ID NO: 70) AKAP7δ-L304T-pep PEDAELVRTSKRLVENAVLKAVQQY (SEQ ID NO: 71) AKAP7δ-L308D-pep PEDAELVRLSKRDVENAVLKAVQQY (SEQ ID NO: 72) AKAP7δ-P-pep PEDAELVRLSKRLPENAVLKAVQQY (SEQ ID NO: 73) AKAP7δ-PP-pep PEDAELVRLSKRLPENAPLKAVQQY (SEQ ID NO: 74) AKAP7δ-L314E-pep PEDAELVRLSKRLVENAVEKAVQQY (SEQ ID NO: 75) AKAP1-pep EEGLDRNEEIKRAAFQIISQVISEA (SEQ ID NO: 76) AKAP2-pep LVDDPLEYQAGLLVQNAIQQAIAEQ (SEQ ID NO: 77) AKAP5-pep QYETLLIETASSLVKNAIQLSIEQL (SEQ ID NO: 78) AKAP9-pep LEKQYQEQLEEEVAKVIVSMSIAFA (SEQ ID NO: 79) AKAP10-pep NTDEAQEELAWKIAKMIVSDIMQQA (SEQ ID NO: 80) AKAP11-pep VNLDKKAVLAEKIVAEAIEKAEREL (SEQ ID NO: 81) AKAP12-pep NGILELETKSSKLVQNIIQTAVDQF (SEQ ID NO: 82) AKAP14-pep TQDKNYEDELTQVALALVEDVINYA (SEQ ID NO: 83) Rab32-pep ETSAKDNINIEEAARFLVEKILVNH (SEQ ID NO: 84)

Residues that were highly conserved among the AD domains of different AKAP proteins are indicated below by underlining with reference to the AKAP IS sequence (SEQ ID NO:3). The residues are the same as observed by Alto et al. (2003), with the addition of the C-terminal alanine residue. (See FIG. 4 of Hundsrucker et al. (2006), incorporated herein by reference.) The sequences of peptide antagonists with particularly high affinities for the RII DDD sequence were those of AKAP-IS, AKAP7δ-wt-pep, AKAP7δ-L304T-pep and AKAP7δ-L308D-pep.

AKAP-IS (SEQ ID NO: 3) QIEYLAKQIVDNAIQQA

Carr et al. (2001, J Biol Chem 276:17332-38) examined the degree of sequence homology between different AKAP-binding DDD sequences from human and non-human proteins and identified residues in the DDD sequences that appeared to be the most highly conserved among different DDD moieties. These are indicated below by underlining with reference to the human PKA RIIα DDD sequence of SEQ ID NO:1. Residues that were particularly conserved are further indicated by italics. The residues overlap with, but are not identical to those suggested by Kinderman et al. (2006) to be important for binding to AKAP proteins. The skilled artisan will realize that in designing sequence variants of DDD, it would be most preferred to avoid changing the most conserved residues (italicized), and it would be preferred to also avoid changing the conserved residues (underlined), while conservative amino acid substitutions may be considered for residues that are neither underlined nor italicized.

(SEQ ID NO: 1) SHIQ IP P GL TELLQGYT V EVLR Q QP P DLVEFA VE YF TR L REA R A 

A modified set of conservative amino acid substitutions for the DDD1 (SEQ ID NO:1) sequence, based on the data of Carr et al. (2001) is shown in Table 5. Even with this reduced set of substituted sequences, there are over 65,000 possible alternative DDD moiety sequences that may be produced, tested and used by the skilled artisan without undue experimentation. The skilled artisan could readily derive such alternative DDD amino acid sequences as disclosed above for Table 2 and Table 3.

TABLE 5 Conservative Amino Acid Substitutions in DDD1 (SEQ ID NO:1). Consensus sequence disclosed as SEQ ID NO: 89. S H I Q I P P G L T E L L Q G Y T V E V L R T N S I L A Q Q P P D L V E F A V E Y F T R L R E A R A N I D S K K L L L I I A  V V

The skilled artisan will realize that these and other amino acid substitutions in the DDD or AD amino acid sequences may be utilized to produce alternative species within the genus of AD or DDD moieties, using techniques that are standard in the field and only routine experimentation.

Amino Acid Substitutions

In alternative embodiments, the disclosed methods and compositions may involve production and use of proteins or peptides with one or more substituted amino acid residues. For example, the DDD and/or AD sequences used to make DNL™ constructs may be modified as discussed above.

The skilled artisan will be aware that, in general, amino acid substitutions typically involve the replacement of an amino acid with another amino acid of relatively similar properties (i.e., conservative amino acid substitutions). The properties of the various amino acids and effect of amino acid substitution on protein structure and function have been the subject of extensive study and knowledge in the art.

For example, the hydropathic index of amino acids may be considered (Kyte & Doolittle, 1982, J. Mol. Biol., 157:105-132). The relative hydropathic character of the amino acid contributes to the secondary structure of the resultant protein, which in turn defines the interaction of the protein with other molecules. Each amino acid has been assigned a hydropathic index on the basis of its hydrophobicity and charge characteristics (Kyte & Doolittle, 1982), these are: isoleucine (+4.5); valine (+4.2); leucine (+3.8); phenylalanine (+2.8); cysteine/cystine (+2.5); methionine (+1.9); alanine (+1.8); glycine (−0.4); threonine (−0.7); serine (−0.8); tryptophan (−0.9); tyrosine (−1.3); proline (−1.6); histidine (−3.2); glutamate (−3.5); glutamine (−3.5); aspartate (−3.5); asparagine (−3.5); lysine (−3.9); and arginine (−4.5). In making conservative substitutions, the use of amino acids whose hydropathic indices are within ±2 is preferred, within ±1 are more preferred, and within ±0.5 are even more preferred.

Amino acid substitution may also take into account the hydrophilicity of the amino acid residue (e.g., U.S. Pat. No. 4,554,101). Hydrophilicity values have been assigned to amino acid residues: arginine (+3.0); lysine (+3.0); aspartate (+3.0); glutamate (+3.0); serine (+0.3); asparagine (+0.2); glutamine (+0.2); glycine (0); threonine (−0.4); proline (−0.5.+−0.1); alanine (−0.5); histidine (−0.5); cysteine (−1.0); methionine (−1.3); valine (−1.5); leucine (−1.8); isoleucine (−1.8); tyrosine (−2.3); phenylalanine (−2.5); tryptophan (−3.4). Replacement of amino acids with others of similar hydrophilicity is preferred.

Other considerations include the size of the amino acid side chain. For example, it would generally not be preferred to replace an amino acid with a compact side chain, such as glycine or serine, with an amino acid with a bulky side chain, e.g., tryptophan or tyrosine. The effect of various amino acid residues on protein secondary structure is also a consideration. Through empirical study, the effect of different amino acid residues on the tendency of protein domains to adopt an alpha-helical, beta-sheet or reverse turn secondary structure has been determined and is known in the art (see, e.g., Chou & Fasman, 1974, Biochemistry, 13:222-245; 1978, Ann. Rev. Biochem., 47: 251-276; 1979, Biophys. J., 26:367-384).

Based on such considerations and extensive empirical study, tables of conservative amino acid substitutions have been constructed and are known in the art. For example: arginine and lysine; glutamate and aspartate; serine and threonine; glutamine and asparagine; and valine, leucine and isoleucine. Alternatively: Ala (A) leu, ile, val; Arg (R) gln, asn, lys; Asn (N) his, asp, lys, arg, gln; Asp (D) asn, glu; Cys (C) ala, ser; Gln (Q) glu, asn; Glu (E) gln, asp; Gly (G) ala; His (H) asn, gln, lys, arg; Ile (I) val, met, ala, phe, leu; Leu (L) val, met, ala, phe, ile; Lys (K) gln, asn, arg; Met (M) phe, ile, leu; Phe (F) leu, val, ile, ala, tyr; Pro (P) ala; Ser (S), thr; Thr (T) ser; Trp (W) phe, tyr; Tyr (Y) trp, phe, thr, ser; Val (V) ile, leu, met, phe, ala.

Other considerations for amino acid substitutions include whether or not the residue is located in the interior of a protein or is solvent exposed. For interior residues, conservative substitutions would include: Asp and Asn; Ser and Thr; Ser and Ala; Thr and Ala; Ala and Gly; Ile and Val; Val and Leu; Leu and Ile; Leu and Met; Phe and Tyr; Tyr and Trp. (See, e.g., PROWL website at rockefeller.edu) For solvent exposed residues, conservative substitutions would include: Asp and Asn; Asp and Glu; Glu and Gln; Glu and Ala; Gly and Asn; Ala and Pro; Ala and Gly; Ala and Ser; Ala and Lys; Ser and Thr; Lys and Arg; Val and Leu; Leu and Ile; Ile and Val; Phe and Tyr. (Id.) Various matrices have been constructed to assist in selection of amino acid substitutions, such as the PAM250 scoring matrix, Dayhoff matrix, Grantham matrix, McLachlan matrix, Doolittle matrix, Henikoff matrix, Miyata matrix, Fitch matrix, Jones matrix, Rao matrix, Levin matrix and Risler matrix (Idem.)

In determining amino acid substitutions, one may also consider the existence of intermolecular or intramolecular bonds, such as formation of ionic bonds (salt bridges) between positively charged residues (e.g., His, Arg, Lys) and negatively charged residues (e.g., Asp, Glu) or disulfide bonds between nearby cysteine residues.

Methods of substituting any amino acid for any other amino acid in an encoded protein sequence are well known and a matter of routine experimentation for the skilled artisan, for example by the technique of site-directed mutagenesis or by synthesis and assembly of oligonucleotides encoding an amino acid substitution and splicing into an expression vector construct.

Therapeutic Agents

In alternative embodiments, therapeutic agents such as cytotoxic agents, anti-angiogenic agents, pro-apoptotic agents, antibiotics, hormones, hormone antagonists, chemokines, drugs, prodrugs, toxins, enzymes or other agents may be used, either conjugated to the subject bsAbs or separately administered before, simultaneously with, or after the bsAb. Drugs of use may possess a pharmaceutical property selected from the group consisting of antimitotic, antikinase, alkylating, antimetabolite, antibiotic, alkaloid, anti-angiogenic, pro-apoptotic agents and combinations thereof.

Exemplary drugs of use may include, but are not limited to, 5-fluorouracil, afatinib, aplidin, azaribine, anastrozole, anthracyclines, axitinib, AVL-101, AVL-291, bendamustine, bleomycin, bortezomib, bosutinib, bryostatin-1, busulfan, calicheamycin, camptothecin, carboplatin, 10-hydroxycamptothecin, carmustine, celebrex, chlorambucil, cisplatin (CDDP), Cox-2 inhibitors, irinotecan (CPT-11), SN-38, carboplatin, cladribine, camptothecans, crizotinib, cyclophosphamide, cytarabine, dacarbazine, dasatinib, dinaciclib, docetaxel, dactinomycin, daunorubicin, doxorubicin, 2-pyrrolinodoxorubicine (2P-DOX), cyano-morpholino doxorubicin, doxorubicin glucuronide, epirubicin glucuronide, erlotinib, estramustine, epidophyllotoxin, erlotinib, entinostat, estrogen receptor binding agents, etoposide (VP16), etoposide glucuronide, etoposide phosphate, exemestane, fingolimod, floxuridine (FUdR), 3′,5′-O-dioleoyl-FudR (FUdR-dO), fludarabine, flutamide, farnesyl-protein transferase inhibitors, flavopiridol, fostamatinib, ganetespib, GDC-0834, GS-1101, gefitinib, gemcitabine, hydroxyurea, ibrutinib, idarubicin, idelalisib, ifosfamide, imatinib, L-asparaginase, lapatinib, lenolidamide, leucovorin, LFM-A13, lomustine, mechlorethamine, melphalan, mercaptopurine, 6-mercaptopurine, methotrexate, mitoxantrone, mithramycin, mitomycin, mitotane, navelbine, neratinib, nilotinib, nitrosurea, olaparib, plicomycin, procarbazine, paclitaxel, PCI-32765, pentostatin, PSI-341, raloxifene, semustine, sorafenib, streptozocin, SU11248, sunitinib, tamoxifen, temazolomide (an aqueous form of DTIC), transplatinum, thalidomide, thioguanine, thiotepa, teniposide, topotecan, uracil mustard, vatalanib, vinorelbine, vinblastine, vincristine, vinca alkaloids and ZD1839.

Toxins of use may include ricin, abrin, alpha toxin, saporin, ribonuclease (RNase), e.g., onconase, DNase I, Staphylococcal enterotoxin-A, pokeweed antiviral protein, gelonin, diphtheria toxin, Pseudomonas exotoxin, and Pseudomonas endotoxin.

Chemokines of use may include RANTES, MCAF, MIP1-alpha, MIP1-Beta and IP-10.

In certain embodiments, anti-angiogenic agents, such as angiostatin, baculostatin, canstatin, maspin, anti-VEGF antibodies, anti-P1GF peptides and antibodies, anti-vascular growth factor antibodies, anti-Flk-1 antibodies, anti-Flt-1 antibodies and peptides, anti-Kras antibodies, anti-cMET antibodies, anti-MIF (macrophage migration-inhibitory factor) antibodies, laminin peptides, fibronectin peptides, plasminogen activator inhibitors, tissue metalloproteinase inhibitors, interferons, interleukin-12, IP-10, Gro-ß, thrombospondin, 2-methoxyoestradiol, proliferin-related protein, carboxiamidotriazole, CM101, Marimastat, pentosan polysulphate, angiopoietin-2, interferon-alpha, herbimycin A, PNU145156E, 16K prolactin fragment, Linomide (roquinimex), thalidomide, pentoxifylline, genistein, TNP-470, endostatin, paclitaxel, accutin, angiostatin, cidofovir, vincristine, bleomycin, AGM-1470, platelet factor 4 or minocycline may be of use.

Immunomodulators of use may be selected from a cytokine, a stem cell growth factor, a lymphotoxin, a hematopoietic factor, a colony stimulating factor (CSF), an interferon (IFN), erythropoietin, thrombopoietin and a combination thereof. Specifically useful are lymphotoxins such as tumor necrosis factor (TNF), hematopoietic factors, such as interleukin (IL), colony stimulating factor, such as granulocyte-colony stimulating factor (G-CSF) or granulocyte macrophage-colony stimulating factor (GM-CSF), interferon, such as interferons-α, -β or -λ and stem cell growth factor, such as that designated “S1 factor”. Included among the cytokines are growth hormones such as human growth hormone, N-methionyl human growth hormone, and bovine growth hormone; parathyroid hormone; thyroxine; insulin; proinsulin; relaxin; prorelaxin; glycoprotein hormones such as follicle stimulating hormone (FSH), thyroid stimulating hormone (TSH), and luteinizing hormone (LH); hepatic growth factor; prostaglandin, fibroblast growth factor; prolactin; placental lactogen, OB protein; tumor necrosis factor-α and -ß; mullerian-inhibiting substance; mouse gonadotropin-associated peptide; inhibin; activin; vascular endothelial growth factor; integrin; thrombopoietin (TPO); nerve growth factors such as NGF-ß; platelet-growth factor; transforming growth factors (TGFs) such as TGF-α and TGF-ß; insulin-like growth factor-I and -II; erythropoietin (EPO); osteoinductive factors; interferons such as interferon-α, -β, and -γ; colony stimulating factors (CSFs) such as macrophage-CSF (M-CSF); interleukins (ILs) such as IL-1, IL-1α, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12; IL-13, IL-14, IL-15, IL-16, IL-17, IL-18, IL-21, IL-25, LIF, kit-ligand or FLT-3, angiostatin, thrombospondin, endostatin, tumor necrosis factor and LT.

Radionuclides of use include, but are not limited to—¹¹¹In, ¹⁷⁷Lu, ²¹²Bi, ²¹³Bi, ²¹¹At, ⁶²Cu, ⁶⁷Cu, ⁹⁰Y, ¹²⁵I, ¹³¹I, ³²P, ³³P, ⁴⁷Sc, ¹¹¹Ag, ⁶⁷Ga, ¹⁴²Pr, ¹⁵³Sm, ¹⁶¹Tb, ¹⁶⁶Dy, ¹⁶⁶Ho, ¹⁸⁶Re, ¹⁸⁸Re, ¹⁸⁹Re, ²¹²Pb, ²²³Ra, ²²⁵Ac, ⁵⁹Fe, ⁷⁵Se, ⁷⁷As, ⁸⁹Sr, ⁹⁹Mo, ¹⁰⁵Rh, ¹⁰⁹Pd, ¹⁴³Pr, ¹⁴⁹Pm, ¹⁶⁹Er, ¹⁹⁴Ir, ¹⁹⁸Au, ¹⁹⁹Au, ²¹¹Pb, and ²²⁷Th. The therapeutic radionuclide preferably has a decay-energy in the range of 20 to 6,000 keV, preferably in the ranges 60 to 200 keV for an Auger emitter, 100-2,500 keV for a beta emitter, and 4,000-6,000 keV for an alpha emitter. Maximum decay energies of useful beta-particle-emitting nuclides are preferably 20-5,000 keV, more preferably 100-4,000 keV, and most preferably 500-2,500 keV. Also preferred are radionuclides that substantially decay with Auger-emitting particles. For example, Co-58, Ga-67, Br-80m, Tc-99m, Rh-103m, Pt-109, In-111, Sb-119, 1-125, Ho-161, Os-189m and Ir-192. Decay energies of useful beta-particle-emitting nuclides are preferably <1,000 keV, more preferably <100 keV, and most preferably <70 keV. Also preferred are radionuclides that substantially decay with generation of alpha-particles. Such radionuclides include, but are not limited to: Dy-152, At-211, Bi-212, Ra-223, Rn-219, Po-215, Bi-211, Ac-225, Fr-221, At-217, Bi-213, Th-227 and Fm-255. Decay energies of useful alpha-particle-emitting radionuclides are preferably 2,000-10,000 keV, more preferably 3,000-8,000 keV, and most preferably 4,000-7,000 keV.

Additional potential radioisotopes of use include ¹¹C, ¹³N, ¹⁵O, ⁷⁵Br, ¹⁹⁸Au, ²²⁴Ac, ¹²⁶I, ¹³³I, ⁷⁷Br, ^(113m)In, ⁹⁵Ru, ⁹⁷Ru, ¹⁰³Ru, ¹⁰⁵Ru, ¹⁰⁷Hg, ²⁰³Hg, ^(121m)Te, ^(122m)Te, ^(125m)Te, ¹⁶⁵Tm, ¹⁶⁷Tm, ¹⁶⁸Tm, ¹⁹⁷Pt, ¹⁰⁹Pd, ¹⁰⁵Rh, ¹⁴²Pr, ¹⁴³Pr, ¹⁶¹Tb, ¹⁶⁶Ho, ¹⁹⁹Au, ⁵⁷Co, ⁵⁸Co, ⁵¹Cr, ⁵⁹Fe, ⁷⁵Se, ²⁰¹Tl, ²²⁵Ac, ⁷⁶Br, ¹⁶⁹Yb, and the like. Some useful diagnostic nuclides may include ¹⁸F, ⁵²Fe, ⁶²Cu, ⁶⁴Cu, ⁶⁷Cu, ⁶⁷Ga, ⁶⁸Ga, ⁸⁶Y, ⁸⁹Zr, ⁹⁴Tc, ^(94m)Tc, ^(99m)Tc, or ¹¹¹In.

Therapeutic agents may include a photoactive agent or dye. Fluorescent compositions, such as fluorochrome, and other chromogens, or dyes, such as porphyrins sensitive to visible light, have been used to detect and to treat lesions by directing the suitable light to the lesion. In therapy, this has been termed photoradiation, phototherapy, or photodynamic therapy. See Joni et al. (eds.), PHOTODYNAMIC THERAPY OF TUMORS AND OTHER DISEASES (Libreria Progetto 1985); van den Bergh, Chem. Britain (1986), 22:430. Moreover, monoclonal antibodies have been coupled with photoactivated dyes for achieving phototherapy. See Mew et al., J. Immunol. (1983), 130:1473; idem., Cancer Res. (1985), 45:4380; Oseroff et al., Proc. Natl. Acad. Sci. USA (1986), 83:8744; idem., Photochem. Photobiol. (1987), 46:83; Hasan et al., Prog. Clin. Biol. Res. (1989), 288:471; Tatsuta et al., Lasers Surg. Med. (1989), 9:422; Pelegrin et al., Cancer (1991), 67:2529.

Other useful therapeutic agents may comprise oligonucleotides, especially antisense oligonucleotides that preferably are directed against oncogenes and oncogene products, such as bcl-2 or p53. A preferred form of therapeutic oligonucleotide is siRNA. The skilled artisan will realize that any siRNA or interference RNA species may be attached to an antibody or fragment thereof for delivery to a targeted tissue. Many siRNA species against a wide variety of targets are known in the art, and any such known siRNA may be utilized in the claimed methods and compositions.

Known siRNA species of potential use include those specific for IKK-gamma (U.S. Pat. No. 7,022,828); VEGF, Flt-1 and Flk-1/KDR (U.S. Pat. No. 7,148,342); Bcl2 and EGFR (U.S. Pat. No. 7,541,453); CDC20 (U.S. Pat. No. 7,550,572); transducin (beta)-like 3 (U.S. Pat. No. 7,576,196); KRAS (U.S. Pat. No. 7,576,197); carbonic anhydrase II (U.S. Pat. No. 7,579,457); complement component 3 (U.S. Pat. No. 7,582,746); interleukin-1 receptor-associated kinase 4 (IRAK4) (U.S. Pat. No. 7,592,443); survivin (U.S. Pat. No. 7,608,7070); superoxide dismutase 1 (U.S. Pat. No. 7,632,938); MET proto-oncogene (U.S. Pat. No. 7,632,939); amyloid beta precursor protein (APP) (U.S. Pat. No. 7,635,771); IGF-1R (U.S. Pat. No. 7,638,621); ICAM1 (U.S. Pat. No. 7,642,349); complement factor B (U.S. Pat. No. 7,696,344); p53 (7,781,575), and apolipoprotein B (7,795,421), the Examples section of each referenced patent incorporated herein by reference.

Additional siRNA species are available from known commercial sources, such as Sigma-Aldrich (St Louis, Mo.), Invitrogen (Carlsbad, Calif.), Santa Cruz Biotechnology (Santa Cruz, Calif.), Ambion (Austin, Tex.), Dharmacon (Thermo Scientific, Lafayette, Colo.), Promega (Madison, Wis.), Mirus Bio (Madison, Wis.) and Qiagen (Valencia, Calif.), among many others. Other publicly available sources of siRNA species include the siRNAdb database at the Stockholm Bioinformatics Centre, the MIT/ICBP siRNA Database, the RNAi Consortium shRNA Library at the Broad Institute, and the Probe database at NCBI. For example, there are 30,852 siRNA species in the NCBI Probe database. The skilled artisan will realize that for any gene of interest, either a siRNA species has already been designed, or one may readily be designed using publicly available software tools. Any such siRNA species may be delivered using the subject DNL complexes.

Methods of Therapeutic Treatment

Various embodiments concern methods of treating a cancer in a subject, such as a mammal, including humans, domestic or companion pets, such as dogs and cats, comprising administering to the subject a therapeutically effective amount of a cytotoxic bsAb.

In one embodiment, immunological diseases which may be treated with the subject bsAbs may include, for example, joint diseases such as ankylosing spondylitis, juvenile rheumatoid arthritis, rheumatoid arthritis; neurological disease such as multiple sclerosis and myasthenia gravis; pancreatic disease such as diabetes, especially juvenile onset diabetes; gastrointestinal tract disease such as chronic active hepatitis, celiac disease, ulcerative colitis, Crohn's disease, pernicious anemia; skin diseases such as psoriasis or scleroderma; allergic diseases such as asthma and in transplantation related conditions such as graft versus host disease and allograft rejection.

The administration of the cytotoxic bsAbs can be supplemented by administering concurrently or sequentially a therapeutically effective amount of another antibody that binds to or is reactive with another antigen on the surface of the target cell. Preferred additional MAbs comprise at least one humanized, chimeric or human MAb selected from the group consisting of a MAb reactive with CD4, CD5, CD8, CD14, CD15, CD16, CD19, IGF-1R, CD20, CD21, CD22, CD23, CD25, CD30, CD32b, CD33, CD37, CD38, CD40, CD40L, CD45, CD46, CD52, CD54, CD70, CD74, CD79a, CD80, CD95, CD126, CD133, CD138, CD154, CEACAM5, CEACAM6, B7, AFP, PSMA, EGP-1, EGP-2, carbonic anhydrase IX, PAM4 antigen, MUC1, MUC2, MUC3, MUC4, MUC5, Ia, MIF, HM1.24, HLA-DR, tenascin, Flt-3, VEGFR, P1GF, ILGF, IL-6, IL-25, tenascin, TRAIL-R1, TRAIL-R2, complement factor C5, oncogene product, or a combination thereof. Various antibodies of use, such as anti-CD19, anti-CD20, and anti-CD22 antibodies, are known to those of skill in the art. See, for example, Ghetie et al., Cancer Res. 48:2610 (1988); Hekman et al., Cancer Immunol. Immunother. 32:364 (1991); Longo, Curr. Opin. Oncol. 8:353 (1996), U.S. Pat. Nos. 5,798,554; 6,187,287; 6,306,393; 6,676,924; 7,109,304; 7,151,164; 7,230,084; 7,230,085; 7,238,785; 7,238,786; 7,282,567; 7,300,655; 7,312,318; 7,501,498; 7,612,180; 7,670,804; and U.S. Patent Application Publ. Nos. 20080131363; 20070172920; 20060193865; and 20080138333, the Examples section of each incorporated herein by reference.

The bsAb therapy can be further supplemented with the administration, either concurrently or sequentially, of at least one therapeutic agent. For example, “CVB” (1.5 g/m² cyclophosphamide, 200-400 mg/m² etoposide, and 150-200 mg/m² carmustine) is a regimen used to treat non-Hodgkin's lymphoma. Patti et al., Eur. J. Haematol. 51: 18 (1993). Other suitable combination chemotherapeutic regimens are well-known to those of skill in the art. See, for example, Freedman et al., “Non-Hodgkin's Lymphomas,” in CANCER MEDICINE, VOLUME 2, 3rd Edition, Holland et al. (eds.), pages 2028-2068 (Lea & Febiger 1993). As an illustration, first generation chemotherapeutic regimens for treatment of intermediate-grade non-Hodgkin's lymphoma (NHL) include C-MOPP (cyclophosphamide, vincristine, procarbazine and prednisone) and CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone). A useful second generation chemotherapeutic regimen is m-BACOD (methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, dexamethasone and leucovorin), while a suitable third generation regimen is MACOP-B (methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisone, bleomycin and leucovorin). Additional useful drugs include phenyl butyrate, bendamustine, and bryostatin-1.

The subject bsAbs can be formulated according to known methods to prepare pharmaceutically useful compositions, whereby the bsAb is combined in a mixture with a pharmaceutically suitable excipient. Sterile phosphate-buffered saline is one example of a pharmaceutically suitable excipient. Other suitable excipients are well-known to those in the art. See, for example, Ansel et al., PHARMACEUTICAL DOSAGE FORMS AND DRUG DELIVERY SYSTEMS, 5th Edition (Lea & Febiger 1990), and Gennaro (ed.), REMINGTON'S PHARMACEUTICAL SCIENCES, 18th Edition (Mack Publishing Company 1990), and revised editions thereof.

The subject bsAbs can be formulated for intravenous administration via, for example, bolus injection or continuous infusion. Preferably, the bsAb is infused over a period of less than about 4 hours, and more preferably, over a period of less than about 3 hours. For example, the first bolus could be infused within 30 minutes, preferably even 15 min, and the remainder infused over the next 2-3 hrs. Formulations for injection can be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions can take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the active ingredient can be in powder form for constitution with a suitable vehicle, e.g., sterile pyrogen-free water, before use.

Additional pharmaceutical methods may be employed to control the duration of action of the bsAbs. Control release preparations can be prepared through the use of polymers to complex or adsorb the bsAbs. For example, biocompatible polymers include matrices of poly(ethylene-co-vinyl acetate) and matrices of a polyanhydride copolymer of a stearic acid dimer and sebacic acid. Sherwood et al., Bio/Technology 10: 1446 (1992). The rate of release from such a matrix depends upon the molecular weight of the bsAb, the amount of bsAb within the matrix, and the size of dispersed particles. Saltzman et al., Biophys. J. 55: 163 (1989); Sherwood et al., supra. Other solid dosage forms are described in Ansel et al., PHARMACEUTICAL DOSAGE FORMS AND DRUG DELIVERY SYSTEMS, 5th Edition (Lea & Febiger 1990), and Gennaro (ed.), REMINGTON'S PHARMACEUTICAL SCIENCES, 18th Edition (Mack Publishing Company 1990), and revised editions thereof.

The bsAb may also be administered to a mammal subcutaneously or even by other parenteral routes, such as intravenously, intramuscularly, intraperitoneally or intravascularly. Moreover, the administration may be by continuous infusion or by single or multiple boluses. Preferably, the bsAb is infused over a period of less than about 4 hours, and more preferably, over a period of less than about 3 hours.

More generally, the dosage of an administered bsAb for humans will vary depending upon such factors as the patient's age, weight, height, sex, general medical condition and previous medical history. It may be desirable to provide the recipient with a dosage of bsAb that is in the range of from about 1 mg/kg to 25 mg/kg as a single intravenous infusion, although a lower or higher dosage also may be administered as circumstances dictate. A dosage of 1-20 mg/kg for a 70 kg patient, for example, is 70-1,400 mg, or 41-824 mg/m² for a 1.7-m patient. The dosage may be repeated as needed, for example, once per week for 4-10 weeks, once per week for 8 weeks, or once per week for 4 weeks. It may also be given less frequently, such as every other week for several months, or monthly or quarterly for many months, as needed in a maintenance therapy.

Alternatively, a bsAb may be administered as one dosage every 2 or 3 weeks, repeated for a total of at least 3 dosages. Or, the construct may be administered twice per week for 4-6 weeks. If the dosage is lowered to approximately 200-300 mg/m² (340 mg per dosage for a 1.7-m patient, or 4.9 mg/kg for a 70 kg patient), it may be administered once or even twice weekly for 4 to 10 weeks. Alternatively, the dosage schedule may be decreased, namely every 2 or 3 weeks for 2-3 months. It has been determined, however, that even higher doses, such as 20 mg/kg once weekly or once every 2-3 weeks can be administered by slow i.v. infusion, for repeated dosing cycles. The dosing schedule can optionally be repeated at other intervals and dosage may be given through various parenteral routes, with appropriate adjustment of the dose and schedule.

While the bsAbs may be administered as a periodic bolus injection, in alternative embodiments the bsAbs may be administered by continuous infusion. In order to increase the Cmax and extend the PK of the bsAbs in the blood, a continuous infusion may be administered for example by indwelling catheter. Such devices are known in the art, such as HICKMAN®, BROVIAC® or PORT-A-CATH® catheters (see, e.g., Skolnik et al., Ther Drug Monit 32:741-48, 2010) and any such known indwelling catheter may be used. A variety of continuous infusion pumps are also known in the art and any such known infusion pump may be used. The dosage range for continuous infusion may be between 0.1 and 3.0 mg/kg per day. More preferably, the bsAbs can be administered by intravenous infusions over relatively short periods of 2 to 5 hours, more preferably 2-3 hours.

In preferred embodiments, the bsAbs are of use for therapy of cancer. Examples of cancers include, but are not limited to, carcinoma, lymphoma, glioblastoma, melanoma, sarcoma, and leukemia, myeloma, or lymphoid malignancies. More particular examples of such cancers are noted below and include: squamous cell cancer (e.g., epithelial squamous cell cancer), Ewing sarcoma, Wilms tumor, astrocytomas, lung cancer including small-cell lung cancer, non-small cell lung cancer, adenocarcinoma of the lung and squamous carcinoma of the lung, cancer of the peritoneum, hepatocellular cancer, gastric or stomach cancer including gastrointestinal cancer, pancreatic cancer, glioblastoma multiforme, cervical cancer, ovarian cancer, liver cancer, bladder cancer, hepatoma, hepatocellular carcinoma, neuroendocrine tumors, medullary thyroid cancer, differentiated thyroid carcinoma, breast cancer, ovarian cancer, colon cancer, rectal cancer, endometrial cancer or uterine carcinoma, salivary gland carcinoma, kidney or renal cancer, prostate cancer, vulvar cancer, anal carcinoma, penile carcinoma, as well as head-and-neck cancer. The term “cancer” includes primary malignant cells or tumors (e.g., those whose cells have not migrated to sites in the subject's body other than the site of the original malignancy or tumor) and secondary malignant cells or tumors (e.g., those arising from metastasis, the migration of malignant cells or tumor cells to secondary sites that are different from the site of the original tumor). Cancers conducive to treatment methods of the present invention involves cells which express, over-express, or abnormally express IGF-1R.

Other examples of cancers or malignancies include, but are not limited to: Acute Childhood Lymphoblastic Leukemia, Acute Lymphoblastic Leukemia, Acute Lymphocytic Leukemia, Acute Myeloid Leukemia, Adrenocortical Carcinoma, Adult (Primary) Hepatocellular Cancer, Adult (Primary) Liver Cancer, Adult Acute Lymphocytic Leukemia, Adult Acute Myeloid Leukemia, Adult Hodgkin's Lymphoma, Adult Lymphocytic Leukemia, Adult Non-Hodgkin's Lymphoma, Adult Primary Liver Cancer, Adult Soft Tissue Sarcoma, AIDS-Related Lymphoma, AIDS-Related Malignancies, Anal Cancer, Astrocytoma, Bile Duct Cancer, Bladder Cancer, Bone Cancer, Brain Stem Glioma, Brain Tumors, Breast Cancer, Cancer of the Renal Pelvis and Ureter, Central Nervous System (Primary) Lymphoma, Central Nervous System Lymphoma, Cerebellar Astrocytoma, Cerebral Astrocytoma, Cervical Cancer, Childhood (Primary) Hepatocellular Cancer, Childhood (Primary) Liver Cancer, Childhood Acute Lymphoblastic Leukemia, Childhood Acute Myeloid Leukemia, Childhood Brain Stem Glioma, Childhood Cerebellar Astrocytoma, Childhood Cerebral Astrocytoma, Childhood Extracranial Germ Cell Tumors, Childhood Hodgkin's Disease, Childhood Hodgkin's Lymphoma, Childhood Hypothalamic and Visual Pathway Glioma, Childhood Lymphoblastic Leukemia, Childhood Medulloblastoma, Childhood Non-Hodgkin's Lymphoma, Childhood Pineal and Supratentorial Primitive Neuroectodermal Tumors, Childhood Primary Liver Cancer, Childhood Rhabdomyosarcoma, Childhood Soft Tissue Sarcoma, Childhood Visual Pathway and Hypothalamic Glioma, Chronic Lymphocytic Leukemia, Chronic Myelogenous Leukemia, Colon Cancer, Cutaneous T-Cell Lymphoma, Endocrine Pancreas Islet Cell Carcinoma, Endometrial Cancer, Ependymoma, Epithelial Cancer, Esophageal Cancer, Ewing's Sarcoma and Related Tumors, Exocrine Pancreatic Cancer, Extracranial Germ Cell Tumor, Extragonadal Germ Cell Tumor, Extrahepatic Bile Duct Cancer, Eye Cancer, Female Breast Cancer, Gaucher's Disease, Gallbladder Cancer, Gastric Cancer, Gastrointestinal Carcinoid Tumor, Gastrointestinal Tumors, Germ Cell Tumors, Gestational TROPhoblastic Tumor, Hairy Cell Leukemia, Head and Neck Cancer, Hepatocellular Cancer, Hodgkin's Lymphoma, Hypergammaglobulinemia, Hypopharyngeal Cancer, Intestinal Cancers, Intraocular Melanoma, Islet Cell Carcinoma, Islet Cell Pancreatic Cancer, Kaposi's Sarcoma, Kidney Cancer, Laryngeal Cancer, Lip and Oral Cavity Cancer, Liver Cancer, Lung Cancer, Lymphoproliferative Disorders, Macroglobulinemia, Male Breast Cancer, Malignant Mesothelioma, Malignant Thymoma, Medulloblastoma, Melanoma, Mesothelioma, Metastatic Occult Primary Squamous Neck Cancer, Metastatic Primary Squamous Neck Cancer, Metastatic Squamous Neck Cancer, Multiple Myeloma, Multiple Myeloma/Plasma Cell Neoplasm, Myelodysplastic Syndrome, Myelogenous Leukemia, Myeloid Leukemia, Myeloproliferative Disorders, Nasal Cavity and Paranasal Sinus Cancer, Nasopharyngeal Cancer, Neuroblastoma, Non-Hodgkin's Lymphoma, Nonmelanoma Skin Cancer, Non-Small Cell Lung Cancer, Occult Primary Metastatic Squamous Neck Cancer, Oropharyngeal Cancer, Osteo-/Malignant Fibrous Sarcoma, Osteosarcoma/Malignant Fibrous Histiocytoma, Osteosarcoma/Malignant Fibrous Histiocytoma of Bone, Ovarian Epithelial Cancer, Ovarian Germ Cell Tumor, Ovarian Low Malignant Potential Tumor, Pancreatic Cancer, Paraproteinemias, Polycythemia vera, Parathyroid Cancer, Penile Cancer, Pheochromocytoma, Pituitary Tumor, Primary Central Nervous System Lymphoma, Primary Liver Cancer, Prostate Cancer, Rectal Cancer, Renal Cell Cancer, Renal Pelvis and Ureter Cancer, Retinoblastoma, Rhabdomyosarcoma, Salivary Gland Cancer, Sarcoidosis Sarcomas, Sezary Syndrome, Skin Cancer, Small Cell Lung Cancer, Small Intestine Cancer, Soft Tissue Sarcoma, Squamous Neck Cancer, Stomach Cancer, Supratentorial Primitive Neuroectodermal and Pineal Tumors, T-Cell Lymphoma, Testicular Cancer, Thymoma, Thyroid Cancer, Transitional Cell Cancer of the Renal Pelvis and Ureter, Transitional Renal Pelvis and Ureter Cancer, TROPhoblastic Tumors, Ureter and Renal Pelvis Cell Cancer, Urethral Cancer, Uterine Cancer, Uterine Sarcoma, Vaginal Cancer, Visual Pathway and Hypothalamic Glioma, Vulvar Cancer, Waldenstrom's Macroglobulinemia, Wilms' Tumor, and any other hyperproliferative disease, besides neoplasia, located in an organ system listed above.

The methods and compositions described and claimed herein may be used to treat malignant or premalignant conditions and to prevent progression to a neoplastic or malignant state, including but not limited to those disorders described above. Such uses are indicated in conditions known or suspected of preceding progression to neoplasia or cancer, in particular, where non-neoplastic cell growth consisting of hyperplasia, metaplasia, or most particularly, dysplasia has occurred (for review of such abnormal growth conditions, see Robbins and Angell, BASIC PATHOLOGY, 2d Ed., W. B. Saunders Co., Philadelphia, pp. 68-79 (1976)).

Dysplasia is frequently a forerunner of cancer, and is found mainly in the epithelia. It is the most disorderly form of non-neoplastic cell growth, involving a loss in individual cell uniformity and in the architectural orientation of cells. Dysplasia characteristically occurs where there exists chronic irritation or inflammation. Dysplastic disorders which can be treated include, but are not limited to, anhidrotic ectodermal dysplasia, anterofacial dysplasia, asphyxiating thoracic dysplasia, atriodigital dysplasia, bronchopulmonary dysplasia, cerebral dysplasia, cervical dysplasia, chondroectodermal dysplasia, cleidocranial dysplasia, congenital ectodermal dysplasia, craniodiaphysial dysplasia, craniocarpotarsal dysplasia, craniometaphysial dysplasia, dentin dysplasia, diaphysial dysplasia, ectodermal dysplasia, enamel dysplasia, encephalo-ophthalmic dysplasia, dysplasia epiphysialis hemimelia, dysplasia epiphysialis multiplex, dysplasia epiphysialis punctata, epithelial dysplasia, faciodigitogenital dysplasia, familial fibrous dysplasia of jaws, familial white folded dysplasia, fibromuscular dysplasia, fibrous dysplasia of bone, florid osseous dysplasia, hereditary renal-retinal dysplasia, hidrotic ectodermal dysplasia, hypohidrotic ectodermal dysplasia, lymphopenic thymic dysplasia, mammary dysplasia, mandibulofacial dysplasia, metaphysial dysplasia, Mondini dysplasia, monostotic fibrous dysplasia, mucoepithelial dysplasia, multiple epiphysial dysplasia, oculoauriculovertebral dysplasia, oculodentodigital dysplasia, oculovertebral dysplasia, odontogenic dysplasia, opthalmomandibulomelic dysplasia, periapical cemental dysplasia, polyostotic fibrous dysplasia, pseudoachondroplastic spondyloepiphysial dysplasia, retinal dysplasia, septo-optic dysplasia, spondyloepiphysial dysplasia, and ventriculoradial dysplasia.

Additional pre-neoplastic disorders which can be treated include, but are not limited to, benign dysproliferative disorders (e.g., benign tumors, fibrocystic conditions, tissue hypertrophy, intestinal polyps or adenomas, and esophageal dysplasia), leukoplakia, keratoses, Bowen's disease, Farmer's Skin, solar cheilitis, and solar keratosis.

In preferred embodiments, the method of the invention is used to inhibit growth, progression, and/or metastasis of cancers, in particular those listed above.

Additional hyperproliferative diseases, disorders, and/or conditions include, but are not limited to, progression, and/or metastases of malignancies and related disorders such as leukemia (including acute leukemias (e.g., acute lymphocytic leukemia, acute myelocytic leukemia (including myeloblastic, promyelocytic, myelomonocytic, monocytic, and erythroleukemia)) and chronic leukemias (e.g., chronic myelocytic (granulocytic) leukemia and chronic lymphocytic leukemia)), polycythemia vera, lymphomas (e.g., Hodgkin's disease and non-Hodgkin's disease), multiple myeloma, Waldenstrom's macroglobulinemia, heavy chain disease, and solid tumors including, but not limited to, sarcomas and carcinomas such as fibrosarcoma, myxosarcoma, liposarcoma, chondrosarcoma, osteogenic sarcoma, chordoma, angiosarcoma, endotheliosarcoma, lymphangiosarcoma, lymphangioendotheliosarcoma, synovioma, mesothelioma, Ewing's tumor, leiomyosarcoma, rhabdomyosarcoma, colon carcinoma, pancreatic cancer, breast cancer, ovarian cancer, prostate cancer, squamous cell carcinoma, basal cell carcinoma, adenocarcinoma, sweat gland carcinoma, sebaceous gland carcinoma, papillary carcinoma, papillary adenocarcinomas, cystadenocarcinoma, medullary carcinoma, bronchogenic carcinoma, renal cell carcinoma, hepatoma, bile duct carcinoma, choriocarcinoma, seminoma, embryonal carcinoma, Wilm's tumor, cervical cancer, testicular tumor, lung carcinoma, small cell lung carcinoma, bladder carcinoma, epithelial carcinoma, glioma, astrocytoma, medulloblastoma, craniopharyngioma, ependymoma, pinealoma, emangioblastoma, acoustic neuroma, oligodendroglioma, meningioma, melanoma, neuroblastoma, and retinoblastoma.

Expression Vectors

Still other embodiments may concern DNA sequences comprising a nucleic acid encoding an antibody, antibody fragment, cytokine or constituent fusion protein of a bsAb, such as a DNL™ construct. Fusion proteins may comprise an antibody or fragment or cytokine attached to, for example, an AD or DDD moiety.

Various embodiments relate to expression vectors comprising the coding DNA sequences. The vectors may contain sequences encoding the light and heavy chain constant regions and the hinge region of a human immunoglobulin to which may be attached chimeric, humanized or human variable region sequences. The vectors may additionally contain promoters that express the encoded protein(s) in a selected host cell, enhancers and signal or leader sequences. Vectors that are particularly useful are pdHL2 or GS. More preferably, the light and heavy chain constant regions and hinge region may be from a human EU myeloma immunoglobulin, where optionally at least one of the amino acid in the allotype positions is changed to that found in a different IgG1 allotype, and wherein optionally amino acid 253 of the heavy chain of EU based on the EU number system may be replaced with alanine. See Edelman et al., Proc. Natl. Acad. Sci USA 63: 78-85 (1969). In other embodiments, an IgG1 sequence may be converted to an IgG4 sequence.

The skilled artisan will realize that methods of genetically engineering expression constructs and insertion into host cells to express engineered proteins are well known in the art and a matter of routine experimentation. Host cells and methods of expression of cloned antibodies or fragments have been described, for example, in U.S. Pat. Nos. 7,531,327, 7,537,930, 7,785,880, 8,076,410, 8,153,433 and 8,372,603, the Examples section of each incorporated herein by reference.

Kits

Various embodiments may concern kits containing components suitable for treating or diagnosing diseased tissue in a patient. Exemplary kits may contain one or more bsAbs as described herein. If the composition containing components for administration is not formulated for delivery via the alimentary canal, such as by oral delivery, a device capable of delivering the kit components through some other route may be included. One type of device, for applications such as parenteral delivery, is a syringe that is used to inject the composition into the body of a subject. Inhalation devices may also be used. In certain embodiments, a therapeutic agent may be provided in the form of a prefilled syringe or autoinjection pen containing a sterile, liquid formulation or lyophilized preparation.

The kit components may be packaged together or separated into two or more containers. In some embodiments, the containers may be vials that contain sterile, lyophilized formulations of a composition that are suitable for reconstitution. A kit may also contain one or more buffers suitable for reconstitution and/or dilution of other reagents. Other containers that may be used include, but are not limited to, a pouch, tray, box, tube, or the like. Kit components may be packaged and maintained sterilely within the containers. Another component that can be included is instructions to a person using a kit for its use.

EXAMPLES

The following examples are provided to illustrate, but not to limit, the claims of the present invention.

Example 1. T-Cell Redirecting Bispecific Antibody DOCK-AND-LOCK™ (DNL™) Complexes

Several species of exemplary T-cell redirecting bispecific antibodies were made as DNL™ complexes, as described below. The complexes were effective to induce an immune response against appropriate target cells.

Materials and Methods

General techniques for making and using DOCK-AND-LOCK™ (DNL™) complexes are described in the Examples below. An exemplary T-cell redirecting bispecific antibody with binding sites for CD3 and CD19 was made as a DNL™ complex, referred to as (19)-3s (FIG. 1). An anti-CD19 F(ab)₂DNL module was constructed by recombinant fusion of a dimerization and docking domain (DDD2) at the carboxyl terminal end of the Fd chain. An anti-CD3-scFv module was designed from Okt3 mAb with addition of an anchor domain (AD2) and assembled in the format V_(H)-L1-V_(K)-L2-6H-L3-AD2 (“6H” disclosed as SEQ ID NO:105), where the V domains were fused via a flexible peptide linker and the AD2 peptide was preceded by a 6-His linker (SE ID NO:105). The sequences of the anti-CD3 variable regions, linkers and AD2 were as shown below.

V_(H) sequence of anti-CD3 scFv (SEQ ID NO: 96) QVQLQQSGAELARPGASVKMSCKASGYTFTRYTMHWVKQRPGQGLEWIGY INPSRGYTNYNQKFKDKATLTTDKSSSTAYMQLSSLTSEDSAVYYCARYY DDHYSLDYWGQGTTLTVSS  L1 Linker (SEQ ID NO: 97) GGGGSGGGGSGGGGS V_(K) sequence of anti-CD3 scFv (SEQ ID NO: 98) DIVLTQSPAIIVISASPGEKVTMTCSASSSVSYMNWYQQKSGTSPKRWIYD TSKLASGVPAHFRGSGSGTSYSLTISGMEAEDAATYYCQQWSSNPFTFGSG TKLEIKR L2 Linker (SEQ ID NO: 99) GGGGS Poly-His-L3 Linker (SEQ ID NO: 100) HREIFIREIGGGSG AD2 (SEQ ID NO: 101) CGQIEYLAKQIVDNAIQQAGC

Expression Vectors and DNL™ Modules—

DNL™ complexes were constructed comprising antibody moieties against various disease-associated antigens, linked to an anti-CD3 antibody moiety, generally abbreviated as (X)-3s bsAbs. Independent production cell lines were developed in SpESFX-10 mouse myeloma cells (Rossi et al., 2011, Biotechnol Prog 27:766-75) for each of the DNL™ modules used to make the (X)-3s bsAbs. A cDNA sequence encoding the Okt3scFv-AD2 polypeptide (SEQ ID NOs:96-101) was synthesized and cloned into the pdHL2 expression vector via 5′ Xba I and 3′ Eag I restriction sites. The construct comprised the V_(H) domain fused to the V_(L) in an scFv with the structure V_(H)-L1-V_(K)-L2-6H-L3-AD2 (“6H” disclosed as SEQ ID NO:105). The expressed protein had two amino acid substitutions from the original Okt3 mAb. A cysteine residue in the CDR-H3 was changed to serine (Kipryanov, 1997, J Immunol Methods 200:69-77). The penultimate residue of the V_(L) was changed from aspartate to lysine.

The Okt3scFv-AD2 module was combined with various C_(H)1-DDD2-Fab modules to generate a panel of (X)-3s trivalent bsAbs (Table 6). The C_(H)1-DDD2-Fab-pdHL2 expression vectors were constructed as described previously for similar constructs (Rossi et al., 2008, Cancer Res 68:8384-92). Briefly, expression vectors encoding C_(H)1-DDD2-Fab were generated from the corresponding IgG-pdHL2 expression vectors by excising the coding sequence for the C_(H)1-Hinge-C_(H)2-C_(H)3 domains with Sac II and Eag I restriction enzymes and replacing it with a 507 bp sequence encoding C_(H)1-DDD2, which was excised from the C_(H)1-DDD2-Fab-hA20-pdHL2 expression vector (Rossi et al., 2008, Cancer Res 68:8384-92) with the same enzymes. C_(H)1-DDD2-Fab modules were derived from the humanized mAbs hA19 (anti-CD19), labetuzumab (hMN-14, anti-CEACAM5), clivatuzumab (hPAM4, anti-mucin), hMN-15 (anti-CEACAM6), hRS7 (anti-TROP-2), veltuzumab (hA20, anti-CD20), hL243 (anti-HLA-DR) and epratuzumab (hLL2, anti-CD22). The mAb designated hA19 was humanized from the mouse anti-CD19 mAb B43 (Uckun et al., 1988, Blood 71:13-29). Each expression vector was linearized by digestion with Sal I restriction enzyme and used to transfect SpESFX-10 cells by electroporation.

Clones were selected in media containing 0.2 μM methotrexate (MTX) and screened for protein expression by ELISA. Okt3scFv-AD2 was captured on Ni-NTA HisSorb plates (Qiagen) and detected with an anti-AD2 mAb. C_(H)1-DDD2-Fab modules were captured with goat-anti-human-kappa chain and detected with goat-anti-human-F(ab′)₂-HRP. Productivity of protein-expression was amplified by stepwise increases in MTX concentration up to 3 μM. Okt3scFv-AD2 and C_(H)1-DDD2-Fab modules were purified to homogeneity from the broth of roller bottle cultures by affinity chromatography using Ni-SEPHAROSE® and Kappa-Select resins, respectively. The DNL™ method was used to assemble (X)-3s bsAbs via the site-specific conjugation of mole equivalents of Okt3scFv-AD2 and C_(H)1-DDD2-Fab modules. For example, approximately 100 mg of (19)-3s were produced by combining 22 mg of Okt3scFv-AD2 with 80 mg of C_(H)1-DDD2-Fab-hA19. The mixture was reduced overnight at room temperature with 1 mM reduced glutathione prior to the addition of 2 mM oxidized glutathione. The (19)-3s was purified from the reaction mixture by sequential affinity chromatography with Kappa-Select and Ni-SEPHAROSE®. Additional (X)-3s constructs were assembled at various scales following a similar process.

TABLE 6 (X)-3s DNL ™ Constructs Code Target C_(H)1-DDD2-Fab AD2-anti-CD3 (19)-3s CD19 C_(H)1-DDD2-Fab-hA19 scFv-AD2-Okt3 (20)-3s CD20 C_(H)1-DDD2-Fab-hA20 scFv-AD2-Okt3 (22)-3s CD22 C_(H)1-DDD2-Fab-hLL2 scFv-AD2-Okt3 (C2)-3s HLA-DR C_(H)1-DDD2-Fab-hL243 scFv-AD2-Okt3 (M1)-3s MUC5AC C_(H)1-DDD2-Fab-hPAM4 scFv-AD2-Okt3 (14)-3s CEACAM5 C_(H)1-DDD2-Fab-hMN-14 scFv-AD2-Okt3 (15)-3s CEACEAM6 C_(H)1-DDD2-Fab-hMN-15 scFv-AD2-Okt3 (E1)-3s TROP-2 C_(H)1-DDD2-Fab-hRS7 scFv-AD2-Okt3

Analytical Methods—

Size-exclusion high-performance liquid chromatography (SE-HPLC) was performed with an Alliance HPLC System with a BIOSUITE™ 250, 4-μm UHR SEC column (Waters Corp). Electrospray ionization time of flight (ESI-TOF) liquid chromatography/mass spectrometry (LC-MS) was performed with a 1200-series HPLC coupled with a 6210 TOF MS (Agilent Technologies, Santa Clara, Calif.). The (19)-3s was resolved by reversed phase HPLC (RP-HPLC) at 60° C., using a 14-min gradient of 30-80% acetonitrile in 0.1% aqueous formic acid with an Aeris widepore 3.6 μm C4 column (Phenomenex). For the TOF MS, the capillary and fragmentor voltages were set to 5500 and 300 V, respectively.

Cell Lines and Reagents—

Raji, Ramos, Daudi, LS174T and Capan-1 cell lines were purchased from the American Type Cell Culture Collection (ATCC, Manassas, Md.) and Nalm-6 cells were purchased from Deutsche Sammlung von Mikroorganismen and Zellinien (DSMZ, Braunchweig, Germany). All cell lines, except Capan-1, were maintained in RPMI-1640 containing 10% FBS, 1% L-glutamine, 1% penicillin-streptomycin and 1% MEM nonessential amino acids. Capan-1 cells were maintained with 20% FBS. All cell culture media and supplements were purchased from Life Technologies (Carlsbad, Calif.).

PBMCs and T Cell Isolation—

Human peripheral blood mononuclear cells (PBMC) were purified from whole donor blood (Blood Center of NJ, East Orange, N.J.) using UNI-SEP_(MAXI) tubes (Novamed, Ltd, Jerusalem, Israel). CD3-positive T cells were isolated from PBMCs by negative selection using the Pan T Cell Isolation Kit (Miltenyi Biotec, Auburn, Calif.), according to the manufacturer's protocol. Efficiency of T cell isolation was assessed by FACS after staining the enriched T cells with anti-CD3-PE antibody. In some cases, further staining with CD-19 and CD-14 was performed as well to identify contaminating cells.

T Cell Activation—

Isolated T cells were plated in 6-well tissue culture plates at a final density of 2.25×10⁶ cells/well. Daudi cells were added to some wells at a final density of 1.5×10⁶ cells/well, other wells were left to contain only T cells. Alternatively, PBMCs were added to 6-well tissue culture plates at a final cell density of 6×10⁶ cells/well. The volume of each well was brought up to 3 mL. To the appropriate wells, 3 ng/mL of (19)-3s, (M1)-3s or (19)-DDD2 was added. After incubation overnight at 37° C., 1 mL of each sample was removed. The cells were pelleted and labeled on ice with CD69-APC and CD3-PE for 20 minutes. Cells were washed 2 times with 1% BSA in PBS and analyzed using a FACSCALIBER™ flow cytometer (BD Biosciences, San Jose, Calif.).

T Cell Proliferation—

PBMCs were seeded in T25 flasks at a concentration of 1×10⁶ cells/mL containing the specified reagents. For B cell-depleted flasks, B cells were removed by negative selection using a B cell isolation kit from Miltenyi according to manufacturer's protocol. On select days, 100 μL of media was removed from each flask, labeled with anti-CD7-APC for 20 minutes on ice, washed once and resuspended in 300 μL of 1% BSA/PBS containing 7-AAD. For each sample, the entire volume is analyzed using a FACSCALIBER™ flow cytometer. Each sample is counted in duplicate. Analysis is performed using FlowJo Software. For each sample, dead (7-AAD+) cells, and debris (based on forward vs. side scatter) was removed. Finally, live CD7+ cells were selected and plotted using Prism software.

Cell Binding Assays (Jurkat/Capan-1)—

Jurkat cells were stained with PKH26 Red Fluorescent Cell Linker Kit (Sigma) according to manufacturer's protocol. Capan-1 cells were stained with 5 μM CFSE (carboxyfluorescein diacetate succinimidyl ester, Life Technologies) according to manufacturer's protocol. Labeled Capan-1 cells were added to 8-well chamber slides (ThermoWaltham, Mass.) and allowed to attach overnight. The following day, media was removed and PKH26-labeled Jurkat cells were added in media containing 0.1 μg/mL of (E1)-3s, (M1)-3s or (19)-3s. Following a 1-hour incubation at 37° C., slides were washed with PBS to remove any unbound cells and observed by fluorescence microscopy.

Cell Binding Assays (Jurkat/Daudi)—

Jurkat and Daudi cells were labeled with anti-CD3-PE and anti-CD2O-FITC, respectively. Labeled cells were then coincubated at a 2.5:1 ratio with 0.1 μg/mL (19)-3s for 30 minutes at room temperature. Aliquots of cells were then observed by fluorescence microscopy.

Cytotoxicity Assay (Hematologic Tumor Cell Lines)—

Target cells were labeled with PKH67 Green Fluorescent Cell Linker Kit (Sigma) according to the manufacturer's protocol. Briefly, 5×10⁶ target cells were resuspended in 250 μL of diluent C. In a second tube 1 μL of PKH26 dye is added to 250 μL of diluent C. The cell suspension is then added to the dye solution, mixed thoroughly and incubated at RT for 2 minutes. The reaction was quenched by adding an equal volume of FBS. The labeled cells were then washed 3 times with complete RPMI. Unstimulated, isolated T cells were used as effector cells. Effector cells and PKH67-labeled target cells were combined at a 10:1 ratio and plated in 48-well plates containing serial dilutions of (19)-3s or (14)-3s. Each well contained 5×10⁴ target cells and 5×10⁵ effector cells. Jeko-1 assays were performed in 20% RPMI. Plates were incubated for 18-24 hours in a 37° C. incubator containing 5% CO₂. Following incubation, all cells were removed from 48-well plates into flow cytometer tubes and resuspended in 1% BSA/PBS containing 1 ug/mL of 7AAD, to distinguish live from dead cells, and 30,000 COUNTBRIGHT™ Absolute Counting Beads (Life Technologies). Cells were analyzed on a FACSCALIBER™ flow cytometer. For each sample, 8,000 COUNTBRIGHT™ beads were counted as a normalized reference. Data were analyzed using FlowJo software (Treestar, Inc., Ashland, Oreg.). For each sample, dead cells and debris were excluded and total live target cells were counted.

Cytotoxicity Assay (Solid Tumor Cell Lines)—

Target cells were labeled with PKH67 Green Fluorescent Cell Linker Kit (Sigma) following the same procedure as for staining with PKH23. Effector cells used were as follows: For Capan-1 assays, CD8+ enriched T cells were used, following purification from a CD8+ enrichment column (R&D Systems, Minneapolis, Minn.). For LS174T cells: Stimulated T cells were used after incubation of PBMC for 5 days in media containing 25 U/mL IL-2 and 50 ng/mL Okt3 Mab, followed by 2 days incubation in media containing 25 U/mL IL-2 alone. Effector cells and PKH67-labeled target cells were combined at a 3:1 ratio (5×10⁴ target cells and 1.5×10⁵ effector cells/well) and plated over 48-well plates containing serial dilutions of (E1)-3s, (14)-3s or (19)-3s. Capan-1 assays were performed in 20% RPMI. Plates were incubated for 42-48 hours in a 37° C. incubator containing 5% CO₂. Following incubation, suspension cells were combined with trypsinized attached cells from all wells and transferred into flow cytometer tubes. Cells were washed one time and resuspended in 1% BSA/PBS containing 1 ug/mL of 7AAD, to distinguish live from dead cells, and 30,000 COUNTBRIGHT™ Absolute Counting Beads. Cells were analyzed on a FACSCALIBER™ flow cytometer. For each sample, 8,000 COUNTBRIGHT™ beads were counted as a normalized reference. Data were analyzed using FlowJo software (Treestar, Inc., Ashland, Oreg.). For each sample, dead cells and debris were excluded and total live target cells were counted.

In Vivo Efficacy—

Female NOD/SCID mice, 8 weeks old, were purchased from Charles River (Wilmington, Mass.). Mice were injected s.c. with a mixture of Raji (1×10⁶) and human PBMCs (5×10⁶ cells) mixed 1:1 with matrigel. Therapy began 1 hour later. Treatment regimens, dosages, and number of animals in each experiment are described in the Results. Animals were monitored daily for signs of tumor out-growth. Once tumors appeared, they were measured twice weekly. Tumor volume (TV) was determined by measurements in two dimensions using calipers, with volumes defined as: L×w²/2, where L is the longest dimension of the tumor and w the shortest. Efficacy was determined by a log-rank test using Prism GraphPad software (v5; LaJolla, Calif.) on Kaplan-Meier curves using survival surrogate endpoints as time for tumor progression (TTP) to 1.0 cm³. Significance was considered at P<0.05.

Results

Construction and Biochemical Analysis of T-Cell Redirecting Bispecific Antibodies.

The DNL™ method was used to generate a panel of (X)-3s, T-cell redirecting bsAbs for targeting of various tumor-associated antigens including CD19, CD20, HLA-DR, TROP-2, CEACAM5 and MUC5AC. The purity of these structures was demonstrated by SE-HPLC and SDS-PAGE analysis, where only bands representing the three constituent polypeptides (Okt3scFv-AD2, hA19-Fd-DDD2 and hA19 kappa) were evident (data not shown). LC-MS analysis identified a single RP-HPLC peak having a deconvoluted mass spectrum consistent (mass accuracy=11 ppm) with the calculated mass (137432.37 Da) of (19)-3s from its deduced amino acid sequence, including the predicted amino-terminal pyroglutamates on the Okt3scFv-AD2 and each of the two C_(H)1-DDD2-hA19 Fd chains (data not shown). No additional post-translational modifications, including glycosylation were indicated.

Immune synapse formation between Daudi Burkitt lymphoma and T cells, mediated by (19)-3s.

The effects of the T-cell redirecting (19)-3s DNL™ complex on targeting effector T cells to CD19⁺ lymphoma cells was examined (FIG. 2). Freshly isolated T cells were combined with Daudi cells at an E:T ratio of 2.5:1. Cells were treated with 0, 1 or 5 μg/mL of (19)-3s DNL™ complex for 30 min at room temperature prior to analysis by flow cytometry. Anti-CD2O-FITC and anti-CD7-APC were used to identify Daudi and T cells, respectively. Co-binding was indicated as the % of CD20⁺/CD7⁺ events. After treatment with (19)-3s, 45.5% of flow events were CD20/CD7 dual-positive, indicating synapsed Daudi and T cells (FIG. 2A), compared to 2% measured for the mixed cells without antibody (FIG. 2B). Addition of (19)-3s resulted in association of >90% of the Daudi with T cells (FIG. 2C). These results show that the (19)-3s DNL™ complex was effective to direct T cells to the targeted antigen-expressing lymphoma cells.

Synapse formation between T cells and target lymphoma cells was demonstrated by fluorescence microscopy (FIG. 3) Jurkat (T cells) and Daudi (B cells) were combined at a 1:1 ratio, treated with 0.1 μg/mL of the (19)-3s DNL™ complex for 30 minutes and stained with anti-CD2O-FITC (FIG. 3A) and anti-CD3-PE (FIG. 3B), prior to analysis by fluorescence microscopy. The merged image (FIG. 3C) reveals synapse formation between green-stained Daudi and red-stained Jurkat cells. Synapse formation was not evident in the absence of (19)-3s (FIG. 3D). FIG. 3C demonstrates that the target lymphoma cells are in direct contact with the targeted T cells.

A dose-response series was performed for (19)-3s mediated association of T cells to an exemplary B-cell lymphoma line (FIG. 4). As shown in FIG. 4, under the conditions of this experiment, saturation of (19)-3s-mediated cell-to-cell association of T cells to target cells was reached at a concentration between 0.037 and 0.111 μg/ml of the DNL™ complex.

FIG. 5 shows a comparison of the relative efficacies of BITE™ (FIG. 5A), DART™ (FIG. 5A) and DNL™ (FIG. 5B) anti-CD3×anti-CD19 complexes for redirecting T cells to targeted CD19⁺ B cells. The data for BITE™ and DART™ was obtained from Moore et al. (2011, Blood 117:4542-51). At the lowest concentration tested of 0.0005 μg/ml, the (19)-3s DNL™ complex was more effective than BITE™ or DART™ at targeting T cells to B-cell lymphoma (FIG. 5). The (19)-3s DNL™ complex also induced a slightly higher maximum level of cell-to-cell association than the comparable BITE™ and DART™ complexes (FIG. 5A). Although difficult to extrapolate from the single data points generated for the (19)-3s DNL™ complex, the EC₅₀ levels appeared to be similar for BITE™, DART™ and DNL™ (FIG. 5).

(19)-3s, (E1)-3s and (M1)-3s-Mediated Cell-Cell Association of T Cells to Target Tumor Cells.

To evaluate the ability of the T-cell redirecting BsAbs to facilitate the association of T cells to their target tumor cells, Jurkat T cells were coincubated with target tumor cells containing (X)-3s and evaluated by flow cytometry and fluorescence microscopy. Jurkat T cells are a CD4+ T cell leukemia line, chosen for their ability to demonstrate T cell binding without depletion of the FITC labeled Daudi cells in the presence of various concentrations of (19)-3s and analyzed by flow cytometry for the detection of double positive (CD3+CD20+) populations indicating T cell-B cell associated complexes. An apparent cell-cell association was seen following treatment with 0.5 ng/mL of (19)-3s and after treatment with 0.1m/mL over 25% of the cell population existed in a cell-cell association (FIG. 5). Fluorescent microscopy supports this data, as immune synapses are evident following treatment with 0.1m/mL (19)-3s (FIG. 4). No synapse formation was seen in the absence of (19)-3s (data not shown).

This cell-cell association was observed in the pancreatic tumor line Capan-1 as well (FIG. 6). Capan-1 expresses high levels of TROP2 and moderate levels of MUC5AC. Therefore, both the TROP2-targeting bsAb, (E1)-3s (FIG. 6C), and MUC5AC-targeting bsAb, (M1)-3s (FIG. 6B) were compared to the non-targeting control bsAb, (19)-3s (FIG. 6A). CF SE-labeled Capan-1 cells were coincubated with PKH26-labeled Jurkat in the presence of these bsAbs. Fluorescent microscopy revealed, as expected, large T-cell/Capan complexes mediated by (E1)-3s, followed by smaller, yet substantial complexes mediated by (M1)-3s and relatively low complex formation following (19)-3s treatment (FIG. 6).

(19)-3s Specifically Induces T Cell Activation and Proliferation.

The ability of (19)-3s to activate T cells was evaluated either in PBMCs (FIG. 7A), or T cells coincubated with Daudi B cells (FIG. 7B), by measuring the expression levels of CD69, an early marker of T cell activation. Treatment with 3 ng/mL of (19)-3s induced T cell activation in T cells coincubated with Daudi B cells as indicated by a >50-fold increase in CD69 expression compared with non-targeting control antibodies, (19)-DDD2 and (M1)-3s, as well as T cells treated with (19)-3s without Daudi target cells (FIG. 7B). Similar results were observed when the antibodies were incubated with PBMCs, containing both T and B cells; (19)-3s stimulated CD69 expression levels >20-fold higher than non-targeting controls (FIG. 7A). In the absence of target cells, purified T cells treated with (19)-3s did not show activation (FIG. 7C).

T cell proliferation, as another indication of T cell activation, was evaluated after treatment of PBMCs with various CD3-targeting antibodies. (19)-3s at 3 nM or 30 pM induced T cell proliferation similar to that of the positive control IL-2/PHA (FIG. 8A). Non-targeting control antibody, (14)-3s, shows some non-specific T cell proliferation at the highest (3 nM) concentration (FIG. 8A). However, T cell proliferation was not observed in PBMCs depleted of B cells (FIG. 8B), suggesting that target cells are necessary for specific (19)-3s induced T cell proliferation.

(X)-3s Re-Directed T-Cell Mediated Killing of Malignant Cell Lines.

The cytotoxicity of each T-cell targeting molecule was evaluated by its ability to mediate lysis of specific tumor target cells. For the hematologic tumor cell lines, a 10:1 E:T ratio using an unstimulated, enriched T cell population as the effector cells in an 18-24 hour assay demonstrated the optimal assay conditions. The CD19-targeting bsAb, (19)-3s induced the most potent specific killing of the relatively low CD19-expressing cell lines Ramos (IC₅₀=0.17 pM, Lysis_(Max)=79%) Daudi (IC₅₀=1 pM, Lysis_(Max)=60%), and Nalm6 (IC₅₀=6 pM, Lysis_(Max)=93%) (FIG. 9A). Interestingly, the high CD19-expressing cell lines, Namalwa (IC₅₀=63 pM, Lysis_(Max)=60%) and Raji (IC₅₀=3 nM, Lysis_(Max)=41%) were the least sensitive to (19)-3s (FIG. 9A). The non-targeting (14)-3s DNL™ construct had little cytotoxic effect in any of the cell lines tested (FIG. 9B). Consistent cytotoxic effects of the (19)-3s construct on the Nalm-6 ALL cell line were obtained with PBMCs obtained from two different donors (FIG. 9C).

The in vitro cytotoxic effects of (20)-3s, (22)-3s and (C2)-3s T-cell redirecting bsAbs were determined in several cell lines (FIG. 10). The CD22-targeting bsAb, (22)-3s, demonstrated potent (IC₅₀=5 pM, Lysis_(Max)=60%) specific T-cell mediated lysis in the CD22-positive Daudi cell line (FIG. 10C), but not in the CD22-negative Namalwa cells (FIG. 10A).

The CD20-targeting bsAb, (20)-3s demonstrated the highest potency in the higher-expressing CD20 cell lines, Daudi (IC₅₀=<0.3 pM, Lysis_(Max)=90%) (FIG. 10C) and Jeko (IC₅₀=1 pM, Lysis_(Max)=90%) (FIG. 10B), compared to the lower CD20-expressing Namalwa cell line (IC₅₀=30 pM, Lysis_(Max)=53%) (FIG. 10A).

The HLA-DR-targeting bsAb, (C2)-3s was tested in the HLA-DR expressing Jeko-1 cell line (IC₅₀=20 pM, Lysis_(Max)=88%) (FIG. 10B).

At an E:T ratio of 10:1, using isolated T cells as effector cells, the bsAbs induced potent T cell-mediated cytotoxicity in various B cell malignancies, including Burkitt lymphoma (Daudi, Ramos, Namalwa) mantle cell lymphoma (Jeko-1) and acute lymphoblastic leukemia (Nalm-6) (Table 7). A non-tumor binding control, (14)-3s, induced only moderate T-cell killing at >10 nM. The nature of the antigen/epitope, particularly its size and proximity to the cell surface, appears to be more important than antigen density for T-cell retargeting potency (Table 7). It is likely that (20)-3s is consistently more potent than (19)-3s and (C2)-3s, even when the expression of CD19 or HLA-DR is considerably higher than CD20, as seen with Namalwa and Jeko-1, respectively (Table 7). This is likely because the CD20 epitope comprises a small extracellular loop having close proximity to the cell surface. When compared directly using Daudi, (22)-3s was the least potent. Compared to CD19 and CD20, CD22 is expressed at the lowest density, is a rapidly internalizing antigen, and its epitope is further away from the cell surface. Each of these factors may contribute to its reduced potency. Finally, sensitivity to T-cell retargeted killing is cell-line-dependent, as observed using (19)-3s, where Raji (IC₅₀>3 nM) is largely unresponsive yet Ramos (IC₅₀=2 pM) is highly sensitive, even though the former expresses higher CD19 antigen density (Table 7).

In conclusion, (19)-3s, (20)-3s, (22)-3s and (C2)-3s bind to T cells and target B cells simultaneously and induce T-cell-mediated killing in vitro. The modular nature of the DNL method allowed the rapid production of several related conjugates for redirected T-cell killing of various B cell malignancies, without the need for additional recombinant engineering and protein production. The close proximity of the CD20 extracellular epitope to the cell surface resulted in the highest potency for (20)-3s.

TABLE 7 Ex vivo re-directed T-cell killing Antigen Expression² IC₅₀ ⁴(pM) Cell Line Type¹ CD19 CD20 CD22 HLA- (19)-3s (20)- (22)-3s (C2)- Daudi BL 1.00 1.00 1.00 1.00 1 0.3 6 N.D. Ramos BL 0.76 0.65 0.26 0.36 2 0.4 N.D.  2 Nalm-6 ALL 1.63 0.05 0.19 0.17 6 N.D. N.D. N.D. Namalwa BL 0.76 0.11 0.05 0.40 63 30 >3000 N.D. Raji BL 1.41 0.69 0.59 0.84 >3000 N.D. N.D. N.D. Jeko-1 MCL 0.89 1.02 0.05 1.06 3000 1 N.D. 20 ¹BL, Burkitt lymphoma; ALL, acute lymphoblastic leukemia; MCL, mantle cell lymphoma. ²Expression level determined by flow cytometry and normalized to that of Daudi. ³IC₅₀, the picomolar concentration that achieved 50% target cell killing.

The in vitro cytotoxic effects of T-cell redirecting bsAbs were also determined in solid tumor cells (FIG. 11). For the solid tumor cell lines, optimal assay conditions were determined to be a 3:1 E:T ratio using stimulated T cells in a 42-48 hour assay. Each bsAb induced specific T-cell mediated lysis of the tumor target cells. The CEACAM5-expressing colon adenocarcinoma cell line, LS-174T, demonstrated potent specific lysis (IC₅₀=2 pM) following treatment with (14)-3s (FIG. 11A). (E1)-3s mediated potent specific lysis of the TROP2 expressing Capan-1 pancreatic adenocarcinoma cell line (IC₅₀=29 pM) (FIG. 11B). The gastric carcinoma cell line NCI-N87, which expresses high levels of both CEACAM6 and TROP2 demonstrated very potent specific lysis to both T-cell targeting molecules, (15)-3s and (E1)-35 (IC₅₀=3 pM and 0.85 pM respectively) (FIG. 11C). The non-targeting control antibody, (19)-3s, induced low (<20%) non-specific lysis at concentrations >1 nM for Capan-1 and LS174T, and moderate (˜40%) non-specific lysis in NCI-N87 cells (FIG. 11A-C). A summary of the in vitro cytotoxicity data for various T-cell redirecting bsAbs in a variety of tumor cell lines is shown in FIG. 12. The various constructs showed a maximal cell lysis of up to 90% or more of the targeted tumor cells, with IC₅₀ values for cell lines expressing the targeted antiben that were generally in the low picomolar range (FIG. 12).

Example 2. In Vivo Studies of T-Cell Redirecting DNL™ Complex

One potential limitation of small (<60 kDa) scFv-based constructs, such as BITE™ and DART™, is the requirement for administration by long-term continuous infusion, due to their toxicity and rapid clearance from circulation. Because the molecular size of DNL™ bsAbs is above the threshold typically associated with renal clearance, it should exhibit slower clearance from circulation. We measured the pharmacokinetic parameters in mice following a single bolus i.v. injection of 5 mg/kg of the (19)-3s bsAb (data not shown). A biphasic clearance was observed with a t½α and t½β of 1.1 and 5.1 h, respectively, resulting in an area under the curve of 1880 pmol*h/mL (data not shown), which was nearly 6-fold greater than that reported for MT103 (anti-CD19×anti-CD3 BITE™) administered at the same molar concentration (US Patent US2010/0303827A1). The major difference is apparently a longer t½α for (19)-3s (data not shown). Because of the potentially advantageous properties of (19)-3s, we evaluated the possibility of using less frequent dosing schedules rather than daily dosing, which is typically used for BITE™ in animal studies.

A pilot study was performed using Raji human Burkitt lymphoma xenografts in NOD/SCID mice reconstituted with human PBMCs (FIG. 13, FIG. 14). Raji cells (1×10⁶ cells/mouse) were combined with freshly isolated PBMCs (5×10⁶ cells/mouse) from a single healthy donor, mixed 1:1 with matrigel, and injected SC into all of the animals in the study on Day 0. Groups of 5 mice received i.v. injections of (19)-3s totaling 130 μg as a single dose on Day 0 (FIG. 13B), three doses of 43 μg (Days 0, 2 and 4) (FIG. 13C) or five daily doses of 26 μg (Days 0-5) (FIG. 13D). The untreated group (FIG. 13A), which was inoculated with the same cell mixture but did not receive (19)-3s, had a median survival time (MST) of 31 days. Each therapy regimen improved survival (P<0.05), with the three dose (every other day) schedule providing the greatest survival benefit (MST=91 days; P=0.0018 by log-rank analysis).

A follow up study was begun to determine the efficacy of less frequent dosing (FIG. 14). Groups of 9 NOD/SCID mice were inoculated with Raji and PBMCs in a similar fashion as above. In this study, therapy was extended to two weeks, compared to one week in the first study. Groups received i.v. injections of (19)-3s totaling 360 μg as 2×130-μg (FIG. 14B), 4×65-μg (FIG. 14D) or 6×43-μg doses over two weeks (FIG. 14E). An additional group was administered 2×130-μg doses SC, instead of i.v. (FIG. 14C). For comparison, control groups of untreated mice (FIG. 14A) or mice treated with non-targeting (M1)-3s antibody (FIG. 14F) were prepared. As of Day 28, each of the (19)-3s treatment groups had significantly smaller AUC than the untreated control (P<0.05). Surprisingly, two weekly doses via the SC route was apparently as effective as greater frequency i.v. dosing.

In vivo studies were also performed using solid tumors (FIG. 15). NOD/SCID mouse xenografts were prepared as described above, for the LS174T colon adenocarcinoma (FIG. 15A, FIG. 15B) or Capan-1 pancreatic carcinoma (FIG. 15C, FIG. 15D). In each case, mice administered the targeting (E1)-3s (FIG. 15B) or (14)-3s (FIG. 15D) bsAb DNL™ constructs showed improved survival compared to controls.

In conclusion, the T-cell retargeting bsAbs, including (19)-3s, (E1)-35 and (M1)-3s DNL™ constructs, mediated synapse formation between T cells and B cells, colon adenocarcinoma or pancreatic carcinoma cells, respectively, via monovalent and bivalent binding to CD3 and CD19, respectively. T-cell activation, proliferation and target cell killing were induced by the DNL™ bsAbs at pM concentrations in an ex vivo setting. Advantageous properties of the DNL™ bsAbs, including bivalent tumor binding and slower clearance, would allow for less frequent dosing and possibly SC administration, compared to BITE™ or DART™ constructs, which are administered i.v. daily in animal models and as a continuous infusion in the clinic. The modular nature of the DNL™ method allows the rapid production of a large number of related conjugates for redirected T-cell killing of various malignancies, without the need for additional recombinant engineering and protein production.

The person of ordinary skill in the art will realize that other antibodies that bind to CD3, CD19 or other disease-associated antigens are known in the art and any such antibody can be used to make F(ab)₂, scFv or other antibody fragments using techniques well known in the art. Such alternative antibodies or fragments thereof may be utilized in the instant methods and compositions. As discussed below, methods of making DOCK-AND-LOCK™ (DNL™) complexes may be applied to incorporate any known antibodies or antibody fragments into a stable, physiologically active complex.

Example 3. Interferon-α Enhances the Cytotoxic Effect of T-Cell Redirecting Bispecific Antibodies

The therapeutic efficacy of the (E1)-35 anti-TROP-2×anti-CD3 bispecific antibody, made from hRS7 and OKT3 as a DNL™ complex, was tested for its ability to delay tumor outgrowth of Capan-1 human pancreatic adenocarcinoma tumor cells when mixed with human T-cells and injected into mice. The effect of interferon-α (either in the form of E1*-2b or PEGASYS) when combined with this therapy was also evaluated.

Methods

Five week-old female NOD/SCID mice were injected s.c. with a mixture of Capan-1 (5×10⁶) and human T-cells (2.5×10⁶ cells) mixed 1:1 with matrigel (E:T ratio of 1:2). There were six different treatment groups of 8 mice each. Treatment consisted of one group receiving 47 μg (E1)-3s i.v. every day for five days starting 1 hour after the administration of the Capan-1/T-cell mixture. Two groups were treated with equimolar amounts of IFN, one received the DNL molecule made from IFN-α2b-DDD2-CK-hRS7 IgG1 (E1*-2b; 2.5 μg s.c. weekly×4 wks) while another received PEGASYS (Roche; 0.6 μg s.c. weekly×4 wks). Two other groups received a combination of (E1)-3s plus E1*2b or (E1)-3s plus PEGASYS. The final group control group remained untreated. Table 7 summarizes the various treatment groups.

TABLE 7 Treatment Groups for (E1)-3s Therapy (E1)-3s Therapy of a Human Pancreatic Carcinoma Xenograft (Capan-1) in NOD/SCID Mice Group (N) Amount Injected Schedule 1 8 Untreated N.A. 2 8 (E1)-3s qdx5 (47 μg i.v.) 3 8 E1*-2b qwkx4 (2.5 μg s.c.) 4 8 PEGASYS qwkx4 (0.6 μg s.c.) 5 8 (E1)-3s + qdx5 + E1*-2b qwkx4 6 8 (E1)-3s + qdx5 + PEGASYS qwkx4

Mice were monitored daily for signs of tumor out-growth. All animals had their tumors measured twice weekly once tumors began to come up. Mice were euthanized for disease progression if their tumor volumes exceeded 1.0 cm³ in size.

Results

Mean tumor volumes for the various groups are shown in FIG. 16. The data containing PEGASYS® groups (FIG. 16B) are shown on a separate graph from the E1*2b groups (FIG. 16A) for clarity. All treatments were significantly better at controlling tumor growth in terms of area-under-the-curve (AUC) when compared to the untreated mice out to day 29, which was when the first mouse in the untreated group was euthanized for disease progression (P<0.0009; AUC_(29 days)). Combining (E1)-35 with PEGASYS® resulted in the best anti-tumor response overall in terms of tumor out-growth (FIG. 16B). This treatment was significantly better than any of the individual treatments (P<0.042; AUC) as well as superior to the combination of (E1)-3s plus E1*-2b (P=0.0312; AUC_(53 days)) (FIG. 16A). The combination of (E1)-3s plus E1*2b could significantly control tumor growth when compared to E1*2b or PEGASYS® alone (P<0.0073; AUC_(46 days)) but not (E1)-3s alone (FIG. 16A-B). There were no significant differences between mice treated with (E1)-3s, PEGASYS®, or E1*-2b (FIG. 16A-B).

In terms of survival, all treatments provide a significant survival benefit when compared to the untreated mice (P<0.0112; log-rank) (FIG. 17). As of day 81, there was no significant difference in median survival times (MST) between mice treated with the combination of (E1)-3s plus E1*-2b and those treated (E1)-3s plus PEGASYS® (MST=79.5 and >81 days, respectively) (FIG. 17). The mice treated with (E1)-3s plus PEGASYS® had a significantly improved survival outcome than any of the individual treatments (P<0.0237) (FIG. 17). Mice treated with (E1)-3s plus E1*2b had a survival benefit when compare to mice treated with either E1*-2b or PEGASYS® alone (MST=53 days for both; P<0.0311) but not when compared to mice treated with just (E1)-3s (MST=68 days) (FIG. 17). Treatment with (E1)-3s provided a significant improvement in survival when compared to mice treated with E1*-2b (P=0.0406) but not when compared to mice treated with PEGASYS® alone (FIG. 17). There was no significant differences between mice treated with only E1*2b and those treated with PEGASYS® alone (FIG. 17).

The results demonstrate that addition of interferon-α provides a substantial increase in survival and decrease in tumor growth when combined with a T-cell redirecting bsAb. The person of ordinary skill will realize that the improved efficacy observed with addition of type I or type III interferons (interferon-α, interferon-β, or interferon-λ) is not limited to the specific (E1)-3s bsAb, but will be observed with other T-cell redirecting bsAbs, made either as DNL™ complexes or in other forms, such as BITE™ or DART™.

Example 4. General Techniques for DOCK-AND-LOCK™

The general techniques discussed below may be used to generate DNL™ complexes with AD or DDD moieties attached to any antibodies or antigen-binding antibody fragments, using the disclosed methods and compositions.

Expression Vectors

The plasmid vector pdHL2 has been used to produce a number of antibodies and antibody-based constructs. See Gillies et al., J Immunol Methods (1989), 125:191-202; Losman et al., Cancer (Phila) (1997), 80:2660-6. The di-cistronic mammalian expression vector directs the synthesis of the heavy and light chains of IgG. The vector sequences are mostly identical for many different IgG-pdHL2 constructs, with the only differences existing in the variable domain (V_(H) and V_(L)) sequences. Using molecular biology tools known to those skilled in the art, these IgG expression vectors can be converted into Fab-DDD or Fab-AD expression vectors.

To generate Fab-DDD expression vectors, the coding sequences for the hinge, CH2 and CH3 domains of the heavy chain were replaced with a sequence encoding the first 4 residues of the hinge, a 14 residue linker and a DDD moiety, such as the first 44 residues of human MIIα (referred to as DDD1, SEQ ID NO:1). To generate Fab-AD expression vectors, the sequences for the hinge, CH2 and CH3 domains of IgG were replaced with a sequence encoding the first 4 residues of the hinge, a 15 residue linker and an AD moiety, such as a 17 residue synthetic AD called AKAP-IS (referred to as AD1, SEQ ID NO:3), which was generated using bioinformatics and peptide array technology and shown to bind RIIα dimers with a very high affinity (0.4 nM). See Alto, et al. Proc. Natl. Acad. Sci., U.S.A (2003), 100:4445-50. Two shuttle vectors were designed to facilitate the conversion of IgG-pdHL2 vectors to either Fab-DDD1 or Fab-AD1 expression vectors, as described below.

Preparation of CH1

The CH1 domain was amplified by PCR using the pdHL2 plasmid vector as a template. The left PCR primer consisted of the upstream (5′) end of the CH1 domain and a SacII restriction endonuclease site, which is 5′ of the CH1 coding sequence. The right primer consisted of the sequence coding for the first 4 residues of the hinge (PKSC, SEQ ID NO:102) followed by four glycines and a serine, with the final two codons (GS) comprising a Bam HI restriction site. The 410 bp PCR amplimer was cloned into the PGEMT® PCR cloning vector (PROMEGA®, Inc.) and clones were screened for inserts in the T7 (5′) orientation.

A duplex oligonucleotide was synthesized to code for the amino acid sequence of DDD1 preceded by 11 residues of the linker peptide, with the first two codons comprising a BamHI restriction site. A stop codon and an EagI restriction site are appended to the 3′ end. The encoded polypeptide sequence is shown below.

(SEQ ID NO: 103) GSGGGGSGGGGSHIQIPPGLTELLQGYTVEVLRQQPPDLVEFAVEYFTRL REARA

Two oligonucleotides, designated RIIA1-44 top and RIIA1-44 bottom, which overlap by 30 base pairs on their 3′ ends, were synthesized and combined to comprise the central 154 base pairs of the 174 bp DDD1 sequence. The oligonucleotides were annealed and subjected to a primer extension reaction with Taq polymerase. Following primer extension, the duplex was amplified by PCR. The amplimer was cloned into PGEMT® and screened for inserts in the T7 (5′) orientation.

A duplex oligonucleotide was synthesized to code for the amino acid sequence of AD1 preceded by 11 residues of the linker peptide with the first two codons comprising a BamHI restriction site. A stop codon and an EagI restriction site are appended to the 3′ end. The encoded polypeptide sequence is shown below.

(SEQ ID NO: 104) GSGGGGSGGGGSQIEYLAKQIVDNAIQQA

Two complimentary overlapping oligonucleotides encoding the above peptide sequence, designated AKAP-IS Top and AKAP-IS Bottom, were synthesized and annealed. The duplex was amplified by PCR. The amplimer was cloned into the PGEMT® vector and screened for inserts in the T7 (5′) orientation.

Ligating DDD1 with CH1

A 190 bp fragment encoding the DDD1 sequence was excised from PGEMT® with BamHI and NotI restriction enzymes and then ligated into the same sites in CH1-PGEMT® to generate the shuttle vector CH1-DDD1-PGEMT®.

Ligating AD1 with CH1

A 110 bp fragment containing the AD1 sequence was excised from PGEMT® with BamHI and NotI and then ligated into the same sites in CH1-PGEMT® to generate the shuttle vector CH1-AD1-PGEMT®.

With this modular design either CH1-DDD1 or CH1-AD1 can be incorporated into any IgG construct in the pdHL2 vector. The entire heavy chain constant domain is replaced with one of the above constructs by removing the SacII/EagI restriction fragment (CH1-CH3) from pdHL2 and replacing it with the SacII/EagI fragment of CH1-DDD1 or CH1-AD1, which is excised from the respective PGEMT® shuttle vector.

C-DDD2-Fd-hMN-14-pdHL2

C-DDD2-Fd-hMN-14-pdHL2 is an expression vector for production of C-DDD2-Fab-hMN-14, which possesses a dimerization and docking domain sequence of DDD2 (SEQ ID NO:2) appended to the carboxyl terminus of the Fd of hMN-14 via a 14 amino acid residue Gly/Ser peptide linker. The fusion protein secreted is composed of two identical copies of hMN-14 Fab held together by non-covalent interaction of the DDD2 domains.

The expression vector was engineered as follows. Two overlapping, complimentary oligonucleotides, which comprise the coding sequence for part of the linker peptide and residues 1-13 of DDD2, were made synthetically. The oligonucleotides were annealed and phosphorylated with T4 PNK, resulting in overhangs on the 5′ and 3′ ends that are compatible for ligation with DNA digested with the restriction endonucleases BamHI and PstI, respectively.

The duplex DNA was ligated with the shuttle vector CH1-DDD1-PGEMT®, which was prepared by digestion with BamHI and PstI, to generate the shuttle vector CH1-DDD2-PGEMT®. A 507 bp fragment was excised from CH1-DDD2-PGEMT® with SacII and EagI and ligated with the IgG expression vector hMN-14(I)-pdHL2, which was prepared by digestion with SacII and EagI. The final expression construct was designated C-DDD2-Fd-hMN-14-pdHL2. Similar techniques have been utilized to generated DDD2-fusion proteins of the Fab fragments of a number of different humanized antibodies.

h679-Fd-AD2-pdHL2

h679-Fab-AD2, was designed to pair to C-DDD2-Fab-hMN-14. h679-Fd-AD2-pdHL2 is an expression vector for the production of h679-Fab-AD2, which possesses an anchoring domain sequence of AD2 (SEQ ID NO:4) appended to the carboxyl terminal end of the CH1 domain via a 14 amino acid residue Gly/Ser peptide linker. AD2 has one cysteine residue preceding and another one following the anchor domain sequence of AD1.

The expression vector was engineered as follows. Two overlapping, complimentary oligonucleotides (AD2 Top and AD2 Bottom), which comprise the coding sequence for AD2 and part of the linker sequence, were made synthetically. The oligonucleotides were annealed and phosphorylated with T4 PNK, resulting in overhangs on the 5′ and 3′ ends that are compatible for ligation with DNA digested with the restriction endonucleases BamHI and SpeI, respectively.

The duplex DNA was ligated into the shuttle vector CH1-AD1-PGEMT®, which was prepared by digestion with BamHI and SpeI, to generate the shuttle vector CH1-AD2-PGEMT®. A 429 base pair fragment containing CH1 and AD2 coding sequences was excised from the shuttle vector with SacII and EagI restriction enzymes and ligated into h679-pdHL2 vector that prepared by digestion with those same enzymes. The final expression vector is h679-Fd-AD2-pdHL2.

Generation of TF2 DNL™ Construct

A trimeric DNL™ construct designated TF2 was obtained by reacting C-DDD2-Fab-hMN-14 with h679-Fab-AD2. A pilot batch of TF2 was generated with >90% yield as follows. Protein L-purified C-DDD2-Fab-hMN-14 (200 mg) was mixed with h679-Fab-AD2 (60 mg) at a 1.4:1 molar ratio. The total protein concentration was 1.5 mg/ml in PBS containing 1 mM EDTA. Subsequent steps involved TCEP reduction, HIC chromatography, DMSO oxidation, and IMP 291 affinity chromatography. Before the addition of TCEP, SE-HPLC did not show any evidence of a₂b formation. Addition of 5 mM TCEP rapidly resulted in the formation of a₂b complex consistent with a 157 kDa protein expected for the binary structure. TF2 was purified to near homogeneity by IMP 291 affinity chromatography (not shown). IMP 291 is a synthetic peptide containing the HSG hapten to which the 679 Fab binds (Rossi et al., 2005, Clin Cancer Res 11:7122s-29s). SE-HPLC analysis of the IMP 291 unbound fraction demonstrated the removal of a₄, a₂ and free kappa chains from the product (not shown).

The functionality of TF2 was determined by BIACORE® assay. TF2, C-DDD1-hMN-14+h679-AD1 (used as a control sample of noncovalent a₂b complex), or C-DDD2-hMN-14+h679-AD2 (used as a control sample of unreduced a₂ and b components) were diluted to 1 μg/ml (total protein) and passed over a sensorchip immobilized with HSG. The response for TF2 was approximately two-fold that of the two control samples, indicating that only the h679-Fab-AD component in the control samples would bind to and remain on the sensorchip. Subsequent injections of WI2 IgG, an anti-idiotype antibody for hMN-14, demonstrated that only TF2 had a DDD-Fab-hMN-14 component that was tightly associated with h679-Fab-AD as indicated by an additional signal response. The additional increase of response units resulting from the binding of WI2 to TF2 immobilized on the sensorchip corresponded to two fully functional binding sites, each contributed by one subunit of C-DDD2-Fab-hMN-14. This was confirmed by the ability of TF2 to bind two Fab fragments of WI2 (not shown).

Production of TF10 DNL™ Construct

A similar protocol was used to generate a trimeric TF10 DNL™ construct, comprising two copies of a C-DDD2-Fab-hPAM4 and one copy of C-AD2-Fab-679. The TF10 bispecific ([hPAM4]₂×h679) antibody was produced using the method disclosed for production of the (anti CEA)₂×anti HSG bsAb TF2, as described above. The TF10 construct bears two humanized PAM4 Fabs and one humanized 679 Fab.

The two fusion proteins (hPAM4-DDD2 and h679-AD2) were expressed independently in stably transfected myeloma cells. The tissue culture supernatant fluids were combined, resulting in a two-fold molar excess of hPAM4-DDD2. The reaction mixture was incubated at room temperature for 24 hours under mild reducing conditions using 1 mM reduced glutathione. Following reduction, the reaction was completed by mild oxidation using 2 mM oxidized glutathione. TF10 was isolated by affinity chromatography using IMP291-affigel resin, which binds with high specificity to the h679 Fab.

Example 5. Production of AD- and DDD-Linked Fab and IgG Fusion Proteins from Multiple Antibodies

Using the techniques described in the preceding Example, the IgG and Fab fusion proteins shown in Table 8 were constructed and incorporated into DNL™ constructs. The fusion proteins retained the antigen-binding characteristics of the parent antibodies and the DNL™ constructs exhibited the antigen-binding activities of the incorporated antibodies or antibody fragments.

TABLE 8 Fusion proteins comprising IgG or Fab Fusion Protein Binding Specificity C-AD1-Fab-h679 HSG C-AD2-Fab-h679 HSG C-(AD)₂-Fab-h679 HSG C-AD2-Fab-h734 Indium-DTPA C-AD2-Fab-hA20 CD20 C-AD2-Fab-hA20L CD20 C-AD2-Fab-hL243 HLA-DR C-AD2-Fab-hLL2 CD22 N-AD2-Fab-hLL2 CD22 C-AD2-IgG-hMN-14 CEACAM5 C-AD2-IgG-hR1 IGF-1R C-AD2-IgG-hRS7 EGP-1 C-AD2-IgG-hPAM4 MUC C-AD2-IgG-hLL1 CD74 C-DDD1-Fab-hMN-14 CEACAM5 C-DDD2-Fab-hMN-14 CEACAM5 C-DDD2-Fab-h679 HSG C-DDD2-Fab-hA19 CD19 C-DDD2-Fab-hA20 CD20 C-DDD2-Fab-hAFP AFP C-DDD2-Fab-hL243 HLA-DR C-DDD2-Fab-hLL1 CD74 C-DDD2-Fab-hLL2 CD22 C-DDD2-Fab-hMN-3 CEACAM6 C-DDD2-Fab-hMN-15 CEACAM6 C-DDD2-Fab-hPAM4 MUC C-DDD2-Fab-hR1 IGF-1R C-DDD2-Fab-hRS7 EGP-1 N-DDD2-Fab-hMN-14 CEACAM5

Example 6. Production and Use of a DNL™ Construct Comprising Two Different Antibody Moieties and a Cytokine

In certain embodiments, trimeric DNL™ constructs may comprise three different effector moieties, for example two different antibody moieties and a cytokine moiety. We report here the generation and characterization of a bispecific MAb-IFNα, designated 20-C2-2b, which comprises two copies of IFN-α2b and a stabilized F(ab)₂ of hL243 (humanized anti-HLA-DR; IMMU-114) site-specifically linked to veltuzumab (humanized anti-CD20). In vitro, 20-C2-2b inhibited each of four lymphoma and eight myeloma cell lines, and was more effective than monospecific CD20-targeted MAb-IFNα or a mixture comprising the parental antibodies and IFNα in all but one (HLA-DR⁻/CD20⁻) myeloma line (not shown), suggesting that 20-C2-2b is useful for the treatment of various hematopoietic disorders. The 20-C2-2b displayed greater cytotoxicity against KMS12-BM (CD20⁺/HLA-DR⁺ myeloma) than monospecific MAb-IFNα that targets only HLA-DR or CD20 (not shown), indicating that all three components in 20-C2-2b can contribute to toxicity.

Antibodies

The abbreviations used in the following discussion are: 20 (C_(H)3-AD2-IgG-v-mab, anti-CD20 IgG DNL™ module); C2 (C_(H)1-DDD2-Fab-hL243, anti-HLA-DR Fab₂ DNL™ module); 2b (dimeric IFNα2B-DDD2 DNL™ module); 734 (anti-in-DTPA IgG DNL™ module used as non-targeting control). The following MAbs were provided by Immunomedics, Inc.: veltuzumab or v-mab (anti-CD20 Ig hL243y4p (Immu-114, anti-HLA-DR IgG₄), a murine anti-IFNα MAb, and rat anti-idiotype MAbs to v-mab (WR2) and hL243 (WT).

DNL™ Constructs

Monospecific MAb-IFNα (20-2b-2b, 734-2b-2b and C2-2b-2b) and the bispecific HexAb (20-C2-C2) were generated by combination of an IgG-AD2-module with DDD2-modules using the DNL™ method, as described in the preceding Examples. The 734-2b-2b, which comprises tetrameric IFNα2b and MAb h734 [anti-Indium-DTPA IgG₁], was used as a non-targeting control MAb-IFNα.

The construction of the mammalian expression vector as well as the subsequent generation of the production clones and the purification of C_(H)3-AD2-IgG-v-mab are disclosed in the preceding Examples. The expressed recombinant fusion protein has the AD2 peptide linked to the carboxyl terminus of the C_(H)3 domain of v-mab via a 15 amino acid long flexible linker peptide. Co-expression of the heavy chain-AD2 and light chain polypeptides results in the formation of an IgG structure equipped with two AD2 peptides. The expression vector was transfected into Sp/ESF cells (an engineered cell line of Sp2/0) by electroporation. The pdHL2 vector contains the gene for dihydrofolate reductase, thus allowing clonal selection, as well as gene amplification with methotrexate (MTX). Stable clones were isolated from 96-well plates selected with media containing 0.2 μM MTX. Clones were screened for C_(H)3-AD2-IgG-vmab productivity via a sandwich ELISA. The module was produced in roller bottle culture with serum-free media.

The DDD-module, IFNα2b-DDD2, was generated as discussed above by recombinant fusion of the DDD2 peptide to the carboxyl terminus of human IFNα2b via an 18 amino acid long flexible linker peptide. As is the case for all DDD-modules, the expressed fusion protein spontaneously forms a stable homodimer.

The C_(H)1-DDD2-Fab-hL243 expression vector was generated from hL243-IgG-pdHL2 vector by excising the sequence for the C_(H)1-Hinge-C_(H)2-C_(H)3 domains with SacII and EagI restriction enzymes and replacing it with a 507 bp sequence encoding C_(H)1-DDD2, which was excised from the C-DDD2-hMN-14-pdHL2 expression vector with the same enzymes. Following transfection of C_(H)1-DDD2-Fab-hL243-pdHL2 into Sp/ESF cells by electroporation, stable, MTX-resistant clones were screened for productivity via a sandwich ELISA using 96-well microtiter plates coated with mouse anti-human kappa chain to capture the fusion protein, which was detected with horseradish peroxidase-conjugated goat anti-human Fab. The module was produced in roller bottle culture.

Roller bottle cultures in serum-free H-SFM media and fed-batch bioreactor production resulted in yields comparable to other IgG-AD2 modules and cytokine-DDD2 modules generated to date. C_(H)3-AD2-IgG-v-mab and IFNα2b-DDD2 were purified from the culture broths by affinity chromatography using MABSELECT™ (GE Healthcare) and HIS-SELECT® HF Nickel Affinity Gel (Sigma), respectively, as described previously (Rossi et al., Blood 2009, 114:3864-71). The culture broth containing the C_(H)1-DDD2-Fab-hL243 module was applied directly to KAPPASELECT® affinity gel (GE-Healthcare), which was washed to baseline with PBS and eluted with 0.1 M Glycine, pH 2.5.

Generation of 20-C2-2b by DNL™

Three DNL™ modules (C_(H)3-AD2-IgG-v-mab, C_(H)1-DDD2-Fab-hL243, and IFN-α2b-DDD2) were combined in equimolar quantities to generate the bsMAb-IFNα, 20-C2-2b. Following an overnight docking step under mild reducing conditions (1 mM reduced glutathione) at room temperature, oxidized glutathione was added (2 mM) to facilitate disulfide bond formation (locking). The 20-C2-2b was purified to near homogeneity using three sequential affinity chromatography steps. Initially, the DNL™ mixture was purified with Protein A (MABSELECT™), which binds the C_(H)3-AD2-IgG-v-MAb group and eliminates un-reacted IFNα2b-DDD2 or C_(H)1-DDD2-Fab-hL243. The Protein A-bound material was further purified by IMAC using HIS-SELECT® HF Nickel Affinity Gel, which binds specifically to the IFNα2b-DDD2 moiety and eliminates any constructs lacking this group. The final process step, using an hL243-anti-idiotype affinity gel removed any molecules lacking C_(H)1-DDD2-Fab-hL243.

The skilled artisan will realize that affinity chromatography may be used to purify DNL™ complexes comprising any combination of effector moieties, so long as ligands for each of the three effector moieties can be obtained and attached to the column material. The selected DNL™ construct is the one that binds to each of three columns containing the ligand for each of the three effector moieties and can be eluted after washing to remove unbound complexes.

The following Example is representative of several similar preparations of 20-C2-2b. Equimolar amounts of C_(H)3-AD2-IgG-v-mab (15 mg), C_(H)1-DDD2-Fab-hL243 (12 mg), and IFN-α2b-DDD2 (5 mg) were combined in 30-mL reaction volume and 1 mM reduced glutathione was added to the solution. Following 16 h at room temperature, 2 mM oxidized glutathione was added to the mixture, which was held at room temperature for an additional 6 h. The reaction mixture was applied to a 5-mL Protein A affinity column, which was washed to baseline with PBS and eluted with 0.1 M Glycine, pH 2.5. The eluate, which contained ˜20 mg protein, was neutralized with 3 M Tris-HCl, pH 8.6 and dialyzed into HIS-SELECT® binding buffer (10 mM imidazole, 300 mM NaCl, 50 mM NaH₂PO₄, pH 8.0) prior to application to a 5-mL HIS-SELECT® IMAC column. The column was washed to baseline with binding buffer and eluted with 250 mM imidazole, 150 mM NaCl, 50 mM NaH₂PO₄, pH 8.0.

The IMAC eluate, which contained ˜11.5 mg of protein, was applied directly to a WP (anti-hL243) affinity column, which was washed to baseline with PBS and eluted with 0.1 M glycine, pH 2.5. The process resulted in 7 mg of highly purified 20-C2-2b. This was approximately 44% of the theoretical yield of 20-C2-2b, which is 50% of the total starting material (16 mg in this example) with 25% each of 20-2b-2b and 20-C2-C2 produced as side products.

Generation and Characterization of 20-C2-2b

The bispecific MAb-IFNα was generated by combining the IgG-AD2 module, C_(H)3-AD2-IgG-v-mab, with two different dimeric DDD-modules, C_(H)1-DDD2-Fab-hL243 and IFNα2b-DDD2. Due to the random association of either DDD-module with the two AD2 groups, two side-products, 20-C2-C2 and 20-2b-2b are expected to form, in addition to 20-C2-2b.

Non-reducing SDS-PAGE (not shown) resolved 20-C2-2b (˜305 kDa) as a cluster of bands positioned between those of 20-C2-C2 (˜365 kDa) and 20-2b-2b (255 kDa). Reducing SDS-PAGE resolved the five polypeptides (v-mab HC-AD2, hL243 Fd-DDD2, IFNα2b-DDD2 and co-migrating v-mab and hL243 kappa light chains) comprising 20-C2-2b (not shown). IFNα2b-DDD2 and hL243 Fd-DDD2 are absent in 20-C2-C2 and 20-2b-2b. MABSELECT™ binds to all three of the major species produced in the DNL™ reaction, but removes any excess IFNα2b-DDD2 and C_(H)1-DDD2-Fab-hL243. The HIS-SELECT® unbound fraction contained mostly 20-C2-C2 (not shown). The unbound fraction from WT affinity chromatography comprised 20-2b-2b (not shown). Each of the samples was subjected to SE-HPLC and immunoreactivity analyses, which corroborated the results and conclusions of the SDS-PAGE analysis.

Following reduction of 20-C2-2b, its five component polypeptides were resolved by RP-HPLC and individual ESI-TOF deconvoluted mass spectra were generated for each peak (not shown). Native, but not bacterially-expressed recombinant IFNα2, is O-glycosylated at Thr-106 (Adolf et al., Biochem J 1991; 276 (Pt 2):511-8). We determined that ˜15% of the polypeptides comprising the IFNα2b-DDD2 module are 0-glycosylated and can be resolved from the non-glycosylated polypeptides by RP-HPLC and SDS-PAGE (not shown). LC/MS analysis of 20-C2-2b identified both the 0-glycosylated and non-glycosylated species of IFNα2b-DDD2 with mass accuracies of 15 ppm and 2 ppm, respectively (not shown). The observed mass of the 0-glycosylated form indicates an O-linked glycan having the structure NeuGc-NeuGc-Gal-GalNAc, which was also predicted (<1 ppm) for 20-2b-2b (not shown). LC/MS identified both v-mab and hL243 kappa chains as well as hL243-Fd-DDD2 (not shown) as single, unmodified species, with observed masses matching the calculated ones (<35 ppm). Two major glycoforms of v-mab HC-AD2 were identified as having masses of 53,714.73 (70%) and 53,877.33 (30%), indicating GOF and G1F N-glycans, respectively, which are typically associated with IgG (not shown). The analysis also confirmed that the amino terminus of the HC-AD2 is modified to pyroglutamate, as predicted for polypeptides having an amino terminal glutamine.

SE-HPLC analysis of 20-C2-2b resolved a predominant protein peak with a retention time (6.7 min) consistent with its calculated mass and between those of the larger 20-C2-C2 (6.6 min) and smaller 20-2b-2b (6.85 min), as well as some higher molecular weight peaks that likely represent non-covalent dimers formed via self-association of IFNα2b (not shown).

Immunoreactivity assays demonstrated the homogeneity of 20-C2-2b with each molecule containing the three functional groups (not shown). Incubation of 20-C2-2b with an excess of antibodies to any of the three constituent modules resulted in quantitative formation of high molecular weight immune complexes and the disappearance of the 20-C2-2b peak (not shown). The HIS-SELECT® and WT affinity unbound fractions were not immunoreactive with WT and anti-IFNα, respectively (not shown). The MAb-IFNα showed similar binding avidity to their parental MAbs (not shown).

IFNα Biological Activity

The specific activities for various MAb-IFNα were measured using a cell-based reporter gene assay and compared to peginterferon alfa-2b (not shown). Expectedly, the specific activity of 20-C2-2b (2454 IU/pmol), which has two IFNα2b groups, was significantly lower than those of 20-2b-2b (4447 IU/pmol) or 734-2b-2b (3764 IU/pmol), yet greater than peginterferon alfa-2b (P<0.001) (not shown). The difference between 20-2b-2b and 734-2b-2b was not significant. The specific activity among all agents varies minimally when normalized to IU/pmol of total IFNα. Based on these data, the specific activity of each IFNα2b group of the MAb-IFNα is approximately 30% of recombinant IFNα2b (4000 IU/pmol).

In the ex-vivo setting, the 20-C2-2b DNL™ construct depleted lymphoma cells more effectively than normal B cells and had no effect on T cells (not shown). However, it did efficiently eliminate monocytes (not shown). Where v-mab had no effect on monocytes, depletion was observed following treatment with hL243α4p and MAb-IFNα, with 20-2b-2b and 734-2b-2b exhibiting similar toxicity (not shown). Therefore, the predictably higher potency of 20-C2-2b is attributed to the combined actions of anti-HLA-DR and IFNα, which may be augmented by HLA-DR targeting. These data suggest that monocyte depletion may be a pharmacodynamic effect associated anti-HLA-DR as well as IFNα therapy; however, this side effect would likely be transient because the monocyte population should be repopulated from hematopoietic stem cells.

The skilled artisan will realize that the approach described here to produce and use bispecific immunocytokine, or other DNL™ constructs comprising three different effector moieties, may be utilized with any combinations of antibodies, antibody fragments, cytokines or other effectors that may be incorporated into a DNL™ construct, for example the combination of anti-CD3 and anti-CD19 or other anti-TAA with IFNα2b.

All of the COMPOSITIONS and METHODS disclosed and claimed herein can be made and used without undue experimentation in light of the present disclosure. While the compositions and methods have been described in terms of preferred embodiments, it is apparent to those of skill in the art that variations maybe applied to the COMPOSITIONS and METHODS and in the steps or in the sequence of steps of the METHODS described herein without departing from the concept, spirit and scope of the invention. More specifically, certain agents that are both chemically and physiologically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims. 

What is claimed is:
 1. A complex comprising: a) a first antibody or antigen-binding fragment thereof conjugated to an AD (anchoring domain) moiety from an AKAP protein, wherein the first antibody or fragment thereof binds to human CD3, wherein amino acid sequence of the first antibody or fragment thereof conjugated to an AD moiety comprises the amino acid sequences of SEQ ID NO:96, SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:100 and SEQ ID NO:101; and b) a second antibody or antigen-binding fragment conjugated to a DDD (dimerization and docking domain) moiety, wherein the amino acid sequence of said DDD moiety is residues 1-44 of human protein kinase A (PKA) RIIα; wherein the second antibody or fragment thereof binds to human MUC5ac and is an hPAM4 antibody; wherein two copies of the DDD moiety form a dimer that binds to one copy of the AD moiety to form the complex.
 2. The complex of claim 1, wherein the first antigen-binding antibody fragment is a scFv.
 3. The complex of claim 1, wherein the second antibody is an IgG antibody.
 4. An antibody fragment comprising the amino acid sequence of SEQ ID NO:98.
 5. An anti-CD3 antibody fragment comprising the amino acid sequences of SEQ ID NO:96, SEQ ID NO:97, SEQ ID NO:98, SEQ ID NO:99, SEQ ID NO:100 and SEQ ID NO:101.
 6. A bispecific antibody comprising an anti-CD3 antibody fragment according to claim
 5. 